Joint Replacement Arthroplasty: Basic Science, Elbow, and Shoulder, Fourth Edition

Chapter 1 History of Elbow Joint Replacement Bernard F. Morrey The early reconstructive precursors of prosthetic replacement were first resection and then interposition arthroplasty (Fig. 1.1).5 , 13 , 31 Interposition arthroplasty itself has a colorful history owing to the interesting variety of substances used as the interposed element. Prosthetic replacement of the elbow was initially prompted by the unpredictable results of these procedures and the dissatisfaction with fusion although interposition was relatively effective at the elbow compared to other joints.13 There was a growing need to address bone resection following trauma. In the late 1940s and early 1950s, replacement of the elbow was undertaken with the use of custom hinged devices, by hemiarthroplasties or proximal ulna articular replacement. In 1952 Venable31 in Europe and in 1965 Barr and Eaton1 in the United States reported on the use of endoprostheses of the distal humerus for reconstructing extensive deficiencies usually following trauma.6 Similar efforts were being introduced around the globe (Fig. 1.2). There were also efforts to create a custom ulnohumeral joint when the elbow was quite unstable and fusion was the only alternative (Fig. 1.3).7 , 18 , 19 All these efforts, however, suffered from poor implant fixation and the inability to stabilize the joint. Hence, early failure was common and late failure predictable. In the l970s, the concept of prosthetic replacement for nontraumatic conditions was expanded to less catastrophic conditions. These designs were intended to address more limited pathology and hence were more aligned with a resurfacing philosophy. Street and Stevens30 are credited with the first use in the United States of a nonstemmed “anatomic” trochlea and capitellum replacement of the distal humerus. Most commonly used for trauma, the goal of these implants was to serve as a hemiarthroplasty replacement that required less bone resection and, hopefully, preservation of the collateral ligaments. A pioneering effort at Mayo in the late 1960s was the first documented attempt to resurface the proximal ulna. The implant was moderately successful even with prolonged follow-up.15

1

Materials such as nylon, acrylic, stainless steel, and even vulcanized rubber were used in the fabrication of these early prostheses. While some were successful in relieving pain, most had limited motion and were often unstable at the site of fixation or at the articulation. Without addressing ligamentous deficiency and implant/bone fixation, they typically failed from loosening or from instability over time. Detailed documentation of these early efforts is quite limited. A few long-term successes were reported; but in general, joint function was limited and the clinical experience consisted of only a few patients or of single case reports. Coonrad3 has nicely characterized the early stages of the development of elbow replacement surgery up to 1980, as shown in Table 1.1.3 The current era of total elbow joint prosthetic replacement was prompted in some measure by the limited success with these custom-designed total or hemireplacements and more influenced by the success of Charnley to secure the implants with polymethylmethacrylate (PMMA). We thus consider the “modern” era of prosthetic replacement to have begun in the early 1970s with an articulated design by Dee,4 which was the first elbow implant to use cement fixation (Fig. 1.4). This implant quickly demonstrated rapid and often disastrous failure along with other designs that were developed with a limited understanding of elbow kinematics but broad-based optimism on the efficacy of PMMA.3 , 4 , 26 , 28 , 29 The lack of understanding of the complex anatomy and biomechanics of this joint that resulted in a particularly high early failure rate that progressed to virtually 100% failure over time with some devices10 prompted the development of a more careful assessment of elbow kinematics22 (Fig. 1.5). The simplistic replication of the elbow by a rigid metal on metal hinge was thus demonstrated to be an obvious oversimplification. Yet, this type of design had a significant and prolonged effect of directing prosthetic design philosophy to avoid all linked implants. The basic mistake was to assume that PMMA would solve all prosthetic or technique shortcomings. Some implants were modified in the early 1970s to address the initial design flaws such as the GSB from Zurich, which allowed some axial translation and axial rotation of the ulna12 (Fig. 1.6). Schlein and Pritchard were two of the first in this country to recognize the value of

2

a “loose hinge” and a polyethylene bushing26 , 28 (Fig. 1.7). Others sought the desirability of an articulation that provided stability and less constraint with a “snap-fit” configuration.14 The snap-fit design by Volz,32 the so-called “Arizona elbow,” also incorporated a radial head to better distribute the forces crossing the joint (Fig. 1.8). Unfortunately, these concepts suffered from deficiencies of design and of technique, especially understanding of the soft tissue balance and articular wear.33 As a more clear understanding of basic elbow mechanics emerged, the initial rigid hinge, 1972 design of Coonrad (Fig. 1.9), was chosen at Mayo to be modified in 1978 according to established biomechanical principles22 and hence became one of the first semiconstrained devices.23 , 21 Today, the semiconstrained linked prosthesis has become the most accepted design concept.2 , 11 Unfortunately, complication rates at the elbow proved very high from loosening, ulnar nerve and wound problems, component fracture, and infection, leading to a 5-year rate of reoperation of 22% to 30%.20 Hence, the whole concept of elbow replacement was abandoned by most and reassessed by few. Early recognition of the obvious problems of tightly linked devices prompted the development of implants that were not mechanically coupled.17 , 34 These so-called resurfacing designs P.3

reflected efforts to remove less bone (Fig. 1.10) and often to restore the anatomic contour and today are appropriately termed unlinked implants.8 , 29 This replacement philosophy was expected to avoid the most common cause of failure, loosening, by allowing the soft tissue capsule and ligaments to transmit load, thus decreasing those forces transmitted at the bone-cement interface. The earliest of these designs also attempted, unsuccessfully, to avoid the use of stems down the canal. This “resurfacing” concept was found to be inadequate due to a high rate of loosening and was abandoned as a concept. Philosophic design directions included implants relatively less constrained, or highly constrained—even if unlinked (Fig. 1.11). Early designs also attempted, unsuccessfully, to avoid bone resection by excluding a stem34 and adding a radial head component to further lessen stresses on the bone-cement interface25 (see Fig. 1.10).

3

FIGURE 1.1 Interposition and resection arthroplasties were the precursors of prosthetic replacement. These were effective procedures at the elbow but suffered from instability and the outcome was often unpredictable.

4

FIGURE 1.2 Early prosthetic replacements were custom-type designs to address bone deficiency usually following trauma. These included distal humeral implants (A) and proximal ulnar implants (B, C). Instability was a frequent problem as is noted in both these instances. P.4

5

FIGURE 1.2 (Continued).

6

FIGURE 1.3 Because of the instability problem, this European design attempted to address this problem with a coupled articulation (A). Unfortunately, fixation proved

7

to be a problem in such early designs (B, C). P.5

TABLE 1.1

First

1885 to 1947

Era of resection, interposition, and anatomic arthroplasty

Second

1947 to 1970

Era of partial and occasional total (straighthinge) joint arthroplasty

Third

1970 to 1975

Era of constrained metal-to-metal, hinge joint replacement with methacrylate fixation

Fourth

1975 to 1980

Era of semiconstrained metal-to-polyethylene hinge or snapfitting prostheses and unconstrained metal-to-polyethylene resurfacing arthroplasty

8

FIGURE 1.4 The first implant to use methylmethacrylate to secure fixation was that designed by Roger Dee (A). Unfortunately, the implant required resection of the distal humerus and failed to replicate normal elbow kinematics (B). Over the years, these theoretical advantages have proved to be more effective in some implants than others (Fig. 1.12).8 , 33 Yet, success is limited to the pathology preserving good bone and ligament substrates. Further, some of the unlinked designs have highly constrained articulation couples, and we now know it is the constraint at the articulation, not the linkage, per se, that influences loosening. Today a much better understanding of elbow kinematics has resulted in the development of more sophisticated implants, instrumentation, and techniques.16 , 27 The concept of a convertible implant is an example of this innovative and evolving thought process (see Chapter 8).

9

MAYO EXPERIENCE Henderson reviewed Mayo's experience with 43 interposition arthroplasties and added an additional 395 from other clinics. His report in the 1918 Journal of Bone and Joint Surgery indicated that interposition arthroplasty at the elbow was second only to the temporomandibular joint for reliability.13 Of interest, 76% were considered “good” at the elbow, and at the knee only 15% were “good.” An occasional custom P.6

hemireplacement was also designed and inserted at Mayo in the 1950s. It appears that one of the first efforts at a resurfacing implant was also developed at Mayo. The so-called “saddle” was designed as a true resurfacing of the ulnar articulation in the late 1960s. It was inserted in several patients, and for some it proved to be quite successful.15 , 24

10

FIGURE 1.5 Basic research in the early 1970s demonstrated that the elbow normally had an axial rotation (A) and a linear change in carrying angle (B) as the elbow went from extension to flexion. These two characteristics were felt to be important in subsequent prosthetic articular designs.

11

In the early 1970s, several additional design concepts were explored at Mayo. These were first uncoupled and conceptual (Fig. 1.13) and subsequently assumed a more anatomic configuration. Inadequate understanding of elbow joint forces and kinematics resulted in rapid failure of the first prototypes. A second-generation device employed a snap-fit design with a radial head component (Fig. 1.14). Although quite reliable for some, problems continued to emerge that related to loosening and radial head malalignment.23 , 33 With a more sophisticated understanding of biomechanics and after studying our own laboratory and clinical data, and that of others, a three-piece, semiconstrained, flanged device was designed in 1978 (Fig. 1.15). Morrey inserted two of these devices and the second one dislocated. The design was immediately abandoned forever. However, the value of the flange concept was felt to be sound and efforts were sought to apply the concept of a flange to an existing design—the Coonrad. In 1978, we determined that the Coonrad linked device was the most attractive and reliable currently available. Based on P.7

recently published biomechanical studies,22 the tight hinge was altered to a semiconstrained articulation with 8 to 10 degrees of varus/valgus and rotatory “play.” This was incorporated into the Coonrad implant design in 1978. This was the Coonrad II device and was used from 1978 to 1981.

12

FIGURE 1.6 The GSB implant was an early metal-on-metal design from Zurich, Switzerland (A). Early failures due to osteolysis from metal debris (B) resulted in

13

continued improvements (C) ultimately resulting in an implant that has proven to be quite effective clinically over a long period of time. P.8

FIGURE 1.7 The concept of a loose bushing was recognized in the early 1970s. The design by Roland Pritchard is an example of this. Note the early concept was of an all-polyethylene humeral component, which was quickly abandoned to its propensity

14

to fracture.

FIGURE 1.8 The recognition of the value of a radial head implant was incorporated in the design by Voltz (A). This implant also attempted to avoid the problems of loosening from rigid hinged articulations by incorporating a snap-fit (B). Unfortunately, problems with radial head alignment and wear causing the snap-fit to become unstable rendered this implant less reliable for a long term. The addition of the anterior flange with a bone graft was incorporated in 1981 and the implant was named the Coonrad/Morrey. The flange plus better intramedullary cavity bone preparation and cementing techniques clearly improved outcomes.9 The Coonrad/Morrey has become the prosthesis of choice at our institution for the majority of patients requiring total elbow arthroplasty since 1985. More recently, O'Driscoll and a design team have revisited the concept of a more anatomic reflection of the joint, which also employs a radial head. Of interest, this design has the added feature of being able to be coupled if the unlinked device appears unstable at the time of implantation (Fig. 1.16) (see Chapter 8). Today, designs continue to emerge and appear more reliable than those of the past. A flanged humeral component is used in many

15

devices. A semiconstrained, linked articulation is also a popular concept. However, in spite of all these advances, the difficulty of reliably addressing elbow pathology is underscored by a complication rate that continues to hover between 15% and 20%. The most interesting current emphasis at the elbow is the development of hemi- or partial replacements (Fig. 1.17). Mayo surgeons have designed such replacements for the radial head (Fig. 1.18) as well as the distal humerus and capitellum (Fig. 1.19) and continue to participate in the evaluation of prosthetic replacement at the elbow. P.9

FIGURE 1.9 A: The initial Coonrad implant also designed in the early 1970s was made of titanium and had a rigid hinge articulation with polyethylene bushings. This device nonetheless proved to be effective but was rendered more effective by subsequent modifications of loosening the articulation to make it semiconstrained and

16

adding a flange to resist the posterior directed forces (B).

FIGURE 1.10 The interest in unlinked implants coincided temporally with those of the linked devices. Note that this early resurfacing type device was designed by Wadsworth in London, England (A). P.10

17

FIGURE 1.10 (Continued). A similar concept was also advanced by James London from California, once again seeking to resurface the joint without the use of stems (B, C).

18

FIGURE 1.11 Some unlinked implants are nonanatomic and minimally constrained such as the Kudo (A). Others are more anatomic and highly constrained such as the Souter-Strathclyde (B). P.11

19

FIGURE 1.12 This design by Roland Pritchard was of an unlinked implant and sought to distribute the forces by adding the radial head implant. Unfortunately, this

20

implant suffered from some design flaws and technically was difficult to properly implant (A). A more anatomic design by Ewald was documented as one of the most successful unlinked implants (B). This device had no radial head component. P.12

FIGURE 1.13 The early Mayo concept by Jim Beckley, MD, was that of a spool with minimal constraints (A). Unfortunately, the stem was the weak link in this design (B) as well as instability. Note the effort to replace the radial head.

21

FIGURE 1.14 The concept of a three-part implant persisted with a snap-fit and a somewhat more anatomic concept. Unfortunately, the offset of the ulnohumeral articulation tended to twist the stem causing a high incidence of loosening. The radial head also failed to properly articulate in many of these patients. P.13

22

FIGURE 1.15 The addition of a flange further enhanced the attractiveness of the early Mayo design. Unfortunately, the snap-fit articulation was not reliable for much

23

of the pathology that was being seen (A). The design was abandoned in 1981 and the flange was incorporated on the Coonrad implant, the articulation of which had been “loosened” in 1978. The addition of the loose hinge and the anterior flange as recommended by the Mayo Clinic became known as the Coonrad/Morrey device (B). P.14

FIGURE 1.16 An additional design from the Mayo Clinic by O'Driscoll and colleagues incorporate the radial head implant with a more sophisticated understanding of the proper implantation and design (A). This implant has the additional feature of being able to be coupled if the uncoupled insertion is unstable or unreliable (B).

24

FIGURE 1.17 Today, the more modern concepts include hemi- and partial replacements. The Latitude humeral hemireplacement has proven effective in a select number of patients (A-D). P.15

25

FIGURE 1.17 (Continued).

26

FIGURE 1.18 Radial head implants are emerging with increased complexity including modularity (A) and an added articulation between the head and stem (B). Both these implants were designed at Mayo. P.16

27

FIGURE 1.19 Patient with capitellar arthritis (A). A capitellar hemireplacement has been designed by Mayo surgeons and can be employed individually or with the radial head (B). The successful implantation is seen on the AP (C) and lateral images (D).

References 1. Barr JS, Eaton RG: Elbow reconstruction with a new prosthesis to replace the distal end of the humerus: A case report. J Bone Joint Surg 47A:1408, 1965. 2. Bell S, Gschwend N, Steiger U: Arthroplasty of the elbow. Experience with the mark III GSB prosthesis. Aust NZJ Surg 56:823, 1986.

28

3. Coonrad RW: History of total elbow arthroplasty. In Inglis AE (ed): Upper Extremity Joint Replacement Symposium on Total Joint Replacement of the Upper Extremity, 1979. St. Louis, C. V. Mosby Co., 1982. 4. Dee R: Total replacement arthroplasty of the elbow for rheumatoid arthritis. J Bone Joint Surg 54B:88, 1972. 5. Dickson RA, Stein H, Bentley G: Excision arthroplasty of the elbow in rheumatoid disease. J Bone Joint Surg 58B:227, 1976. 6. Dunn WA: A distal humeral prosthesis. Clin Orthop 77:199, 1971. 7. Engelbrecht E, Bucholz HW, Rottger J, Siegal A: Total elbow replacement with a hinge and a nonblocked system. In Joint Replacement of the Upper Limb. London, Mechanical Engineering Publications, 1978. P.17

8. Ewald FC: Total elbow replacement. Orthop Clin North Am 6:685, 1975. 9. Faber KY, Cordy ME, Milne AD, et al: Advanced cement technique improves fixation in elbow arthroplasty. Clin Orthop 334:150-156, 1997. 10. Garrett JC, Ewald FC, Thomas WH, Sledge CB: Loosening associated with GSB hinge total elbow replacement in patients with rheumatoid arthritis. Clin Orthop 127:170, 1977. 11. Gill DR, Morrey BF: The Coonrad-Morrey total elbow arthroplasty in patients who have rheumatoid arthritis: A 10 to 15 year follow-up study. J Bone Joint Surg 80A:1327, 1998. 12. Gschwend N, Loehr J, Ivosevic-Radovanovic D, Scheler H: Semiconstrained elbow prostheses with special reference to the GSB III prosthesis. Clin Orthop 232:104, 1988. 13. Henderson MS: Symposium on arthroplasty: What are the real results of arthroplasty. J Bone Joint Surg Am s2-s16:30-33, 1918. 14. Inglis AE, Pellicci PM: Total elbow replacement. J Bone Joint Surg 62A:1252, 1980. 15. Johnson EW Jr, Schlein AP: Vitallium prosthesis for the olecranon and proximal part of the ulna: Case report with thirteen-year follow-up. J Bone Joint Surg 52A:721, 1970.

29

16. Kamineni S, O'Driscoll SW, Urban M, et al: Intrinsic constraint of unlinked total elbow replacements—the ulnotrochlear joint. J Bone Joint Surg 87A(9):2019-2027, 2005. 17. Kudo H, Iwano K, Watanabe S: Total replacement of the rheumatoid elbow with a hingeless prosthesis. J Bone Joint Surg 62A:277, 1980. 18. MacAusland WR: Replacement of the distal end of the humerus with a prosthesis: Report of four cases. West J Surg 65:557, 1954. 19. Mellen RH, Phalen GS: Arthroplasty of the elbow by replacement of the distal end of the humerus with an acrylic prosthesis. J Bone Joint Surg 29:348, 1947. 20. Morrey BF, Bryan RS: Complications of total elbow arthroplasty. Clin Orthop 170:204, 1982. 21. Morrey BF, Bryan RS: Total joint arthroplasty. The elbow. Mayo Clin Proc 54:507, 1979. 22. Morrey BF, Chao EY: Passive motion of the elbow joint. J Bone Joint Surg 58A:501, 1976. 23. Morrey BF, Bryan RS, Dobyns JH, Linscheid RL: Total elbow arthroplasty: A five-year experience at the Mayo Clinic. J Bone Joint Surg 63A:1050, 1981. 24. Peterson LFA, James JA: Surgery of the rheumatoid elbow. Orthop Clin NA 2:667, 1971. 25. Pritchard RW: Anatomic surface elbow arthroplasty: A preliminary report. Clin Orthop 179:223, 1983. 26. Pritchard RW: Long-term follow-up study: Semiconstrained elbow prosthesis. Orthopedics 4:151, 1981. 27. Ramsey M, Neale PG, Morrey BF, et al: Kinematics and functional characteristics of the Pritchard ERS unlinked total elbow arthroplasty. J Shoulder Elbow Surg 12(4):385-390, 2003. 28. Schlein AP: Semiconstrained total elbow arthroplasty. Clin Orthop 121:222, 1976. 29. Souter WA: Arthroplasty of the elbow: With particular reference to metallic hinge arthroplasty in rheumatoid patients. Orthop Clin North Am 4:395, 1973. 30. Street DM, Stevens PS: A humeral replacement prosthesis for the elbow: Results in ten elbows. J Bone Joint Surg 56A:1147, 1974. 31. Venable CS: An elbow and an elbow prosthesis: Case of complete loss of the lower third of the humerus. Am J Surg 83:271, 1952.

30

32. Volz RG: Development and clinical analysis of a new semiconstrained total elbow prosthesis. In Inglis AE (ed): Upper Extremity Joint Replacement Symposium on Total Elbow Joint Replacement of the Upper Extremity, 1979. St. Louis, C. V. Mosby Co., 1982. 33. van Riet RP, Morrey BF, O'Driscoll SW: The Pritchard ERS total elbow prosthesis: Lessons to be learned from failure. J Shoulder Elbow Surg 18(5):791-795, 2009. 34. Wadsworth TG: Prosthetic replacement of the arthritic elbow. Curr Opin Rheumatol 5(3):322-328, 1993.

31

Chapter 2 Anatomy and Surgical Approaches Bernard F. Morrey

ANATOMY This chapter deals with relevant anatomy that relates to what we have found as the most useful exposures for elbow joint replacement.

TOPICAL ANATOMY The appropriate surgical approach to the elbow relies on the recognition of palpable landmarks: the medial and lateral epicondyles,1 the lateral column of the humerus, the tip of the olecranon, and especially the subcutaneous border of the ulna. In virtually all instances, a posterior skin incision is adequate and preferred regardless of the deep exposure being employed.

OSTEOLOGY AND JOINT STRUCTURE A clear understanding of the normal anatomy of all three articular elements of the elbow joint is necessary to reliably perform the full spectrum of reconstructive procedures of this joint.

Humerus What is of particular relevance to joint replacement is the recognition that the articular surface of the trochlea is offset in reference to the medullary canal, which is slightly lateral to the center of the trochlea (Fig. 2.1). Of note is that the center line of the shaft of the humerus bisects the lateral face of the trochlea. This has been shown to be the neutral varus/valgus joint of the elbow.19 Hence, implants centered on the shaft of the humerus in the AP plane will tend to be “balanced” referable to varus/valgus stresses during flexion/extension motion. Proper axial rotation at the time of insertion of the humeral implant is best estimated by the plane formed by the line that connects the origins of the collateral ligaments (Fig. 2.2).17 On the lateral view, the anterior rotation of the articulation measures approximately 30 degrees, and joint replacement devices must be constructed in such a way as to allow replication of the axis of rotation (Fig. 2.2). The normal axis of rotation of the humerus is colinear with a line drawn from the anterior cortex of the distal humerus.

1

The orientation of the axis of rotation referable to the distal humerus in the anteroposterior plane is not at a right angle but rather has a 4- to 7-degree valgus orientation referable to the long axis (Fig. 2.2). Hinged or captive joint replacements P.19

accommodate for the valgus disposition of the articular surface at the ulna.16 Unlinked designs must accurately replicate the valgus tilt at the humerus because this is necessary to properly balance the ligaments and capsule. Hence, unlinked designs may offer variable articular/stem angles of the implant either at the ulna or at the humerus, or both.24

2

FIGURE 2.1 A: Osseous landmarks of the anterior aspect of the distal humerus. B: Posterior aspect of the distal humerus clearly shows the relationship of the all-

3

important medial and lateral supracondylar bony columns.

FIGURE 2.2 The normal flexion axis is defined by a line connecting the epicondyles. This results in a valgus angulation of the AP plane (A); is colinear with the anterior humeral cortex in the lateral projection (B); and is slightly internally rotated referable to the plane of the columns in the axial view (C).

Radius The articular surface is oriented on a 15-degree angle referable to the long axis of the radius, opposite in direction to the radial tuberosity (Fig. 2.3). Recognition of this poorly emphasized relationship allows proper placement of a radial component so that an accurate articulation with the capitellum occurs during pronation and supination. In our experience in the past, accurate radial head replacement has proven to be extremely difficult with most implants which employ a radial head option.

Proximal Ulna The proximal ulna has two subtle angular orientations. First is a slight valgus that averages about 8 to 10 degrees of the articulation referable to the proximal shaft. Most implants restore or replicate the carrying angle by allowing for the valgus angle at the ulnar component (Fig.

4

2.4).2 , 13 On the lateral projection, the center of the articulation is located in the center of the greater sigmoid notch.18 Of importance, the ulna also has a valgus bow that occurs 6 to 8 cm distal to the coronoid.

LIGAMENTS AND CONSTRAINTS Medial Ligament Complex The medial lateral ligament complex consists primarily of the anterior and posterior bundles (Fig. 2.5). The anterior oblique bundle is the most discrete and functionally sufficient component.12 , 19 , 23 The origin of this ligament is on the undersurface of the medial epicondyle, which is on the axis of rotation.18 The insertion of the ligament is at the sublime tubercle of the coronoid process.

5

FIGURE 2.3 Proximal radius has a 15-degree angulation away from the radial tuberosity. P.20

6

FIGURE 2.4 Valgus angulation of the articular proximal ulna is replicated by the design of ulnar implants (A). The center of rotation of the ulnar component is coincident with the center of rotation of the normal elbow lying in the projected center of the greater sigmoid notch (B). The medial proximal bow of the ulna is important when dealing with long-stemmed implants (C). The posterior bundle of the medial collateral ligament is less well defined and can be released with impunity during joint replacement. However, the anterior portion should not be altered, if possible, when implanting an unlinked device because this is necessary for the stability of such implants.

Lateral Ligament Complex The lateral ligament complex consists of the radial collateral ligament, the lateral ulnar collateral ligament, the less important accessory lateral collateral ligament, and the annular ligament (Fig. 2.6).15 The latter two are of minimum relevance in the present context.

7

FIGURE 2.5 Medial aspect of the joint. The anterior and posterior bundles of the medial collateral ligament are consistently present and identifiable.

Lateral Ulnar Collateral Ligament The lateral ulnar collateral ligament has a very similar orientation to the medial ligament and serves as a major stabilizer of the elbow joint (Fig. 2.7). The lateral ulnar collateral ligament also tends to be isometric throughout the arc of elbow flexion.16 It is essential to repair or reconstruct this ligament when employing unlinked implants to avoid rotatory instability.22 P.21

8

FIGURE 2.6 Lateral ligament complex is composed of the radial collateral ligament, the annular ligament, and the increasingly well-recognized lateral ulnar collateral ligament.

MUSCLES ABOUT THE ELBOW Several important aspects referable to pathologic conditions or reconstructive procedures are worthy of note.

Elbow Flexors Biceps The biceps tendon lies very close to the axis of rotation, inserting on the radial tuberosity. The biceps muscle is a reliable flexor even in the most extensively involved joints. Because of this, we tend to not insert but debride the radial head to increase the effectiveness of the biceps muscle to flex and supinate the elbow.17

9

FIGURE 2.7 The origin of the lateral ulnar collateral ligament is at the lateral tubercle, which is the isometric point of origin for the ligament and is coincident with the instant center of rotation (A). On the lateral view, the anterior bundle of the medial ligament origin is just at the anterior/inferior aspect of the medial epicondyle (B).

Brachialis Because the insertion of the brachialis is distal to the tip of the coronoid process, osteophytic changes at the coronoid may be removed without compromising the insertion of the muscle. The origin of this muscle is from the entire anterior distal half of the humerus, which allows safe and ready access to the anterior humeral cortex (Fig. 2.8).9

Muscles Originating from the Lateral Epicondyle

10

The common extensor muscle group includes the extensor carpi radialis longus and brevis and the common extensor of the digits. This common origin is typically left inviolate during P.22

elbow joint replacement. Particular care should be taken to maintain the normal anatomic origin of the common extensors when inserting an unlinked device because the dynamic element provided by these muscles may be important in stabilizing the elbow.

FIGURE 2.8 The brachialis inserts along the anterior aspect of the distal humerus, but the area immediately above the articulation is free of muscular origin, allowing placement of the flange of the Mayomodified Coonrad implant. (From Hollinshead WH: The back and limbs. In Anatomy for Surgeons, vol 3. New York, Harper & Row, 1969, p 379, with permission of Mayo Foundation.)

11

With deformity the lateral muscle/ligament compelx is contracted and will compromise avascular balance. In this setting, the ligament and muscle must be released from the lateral epicondyle.

Elbow Extensors Triceps Brachii The triceps brachii comprises the entire posterior bulk of the musculature of the arm. The tendon attachment is supplemented by medial fascial extensions and the anconeus muscle laterally, a feature employed in the Kocher and Mayo extensile exposures to the joint.4 , 12 It is significant that the distal aspect of the muscle is comprised of a wide superficial fascial layer that blends with the triceps tendon distally.

Anconeus The anconeus muscle originates from a position at the posterior aspect of the lateral epicondyle and from the triceps fascia. It inserts in the lateral dorsal surface of the proximal ulna. The size of this muscle averages 9 × 3 cm.20 Its close approximation and association with the triceps mechanism allow reflection of this muscle with the triceps mechanism during the modified Kocher approach. Furthermore, the attachment to the triceps is useful allowing mobilization for some cases of triceps insufficiency.

Flexor Pronator Group The flexor pronator group of muscles consists of the pronator teres, flexor carpi radialis, flexor carpi ulnaris, palmaris longus, flexor digitorum superficialis, and flexor digitorum profundus. These all have a common origin at the medial epicondyle. The ulnar nerve enters the flexor carpi ulnaris, so this muscle is routinely split to expose the first motor branch when the nerve is translocated at the time of elbow replacement.

VASCULAR ANATOMY The brachial artery is rarely involved by pathologic processes or surgical exposures of the elbow. Although the collateral circulation seems extensive, it may not be adequate to maintain a viable extremity

12

if the artery is injured, ligated, or thrombosed, which sometimes occurs with elbow dislocation.

Radial Artery In most instances, the radial artery originates at the level of the radial head and emerges from the anterior cubital space between the brachioradialis and the pronator teres muscles. It sends off a branch, the radial recurrent artery, ascending laterally through the supinator muscle to anastomose with the radial collateral artery. At the level of the lateral epicondyle, the radial recurrent artery is rarely observed during joint replacement because all exposures are from the posterior. However, the anastomoses can be a source of major bleeding in the elbow if violated during the procedure. The recurrent vessels are ligated during the extensile anterior exposure of Henry.

Ulnar Artery The ulnar artery is the largest of the two terminal branches of the brachial artery. Two recurrent branches originate distal to the origin of the artery, which arises distal to the coronoid. It ascends posterior to the medial epicondyle and accompanies the ulnar nerve to anastomose with the superior ulnar collateral artery. Major branches of the ulnar recurrent artery may be encountered during a dissection that involves the ulnar nerve (Fig. 2.9).27

NERVES All the major nerves, the musculocutaneous, median, radial, and ulnar, give off articular branches to innervate the elbow joint (Fig. 2.10).8

13

FIGURE 2.9 Vascular anatomy of the posterior aspect of the elbow. Branches of the ulnar recurrent artery are encountered with the medial Mayo approach as the ulnar nerve is dissected out of its bed. (From Yamaguchi K, Sweet FA, Bindra R, et al: The extraosseous and intraosseous arterial anatomy of the adult elbow. J Bone Joint Surg

14

79A:1653-1662, 1997, with permission.) P.23

FIGURE 2.10 All the major nerves that cross the elbow contribute articular sensory branches to the joint. (From Gardner E: The innervation of the elbow joint. Anat Rec 102:161, 1948, with permission.)

Median Nerve The median nerve enters the anterior aspect of the brachium and crosses in front of the brachial artery as it passes across the intermuscular septum. It follows a straight course medial to the midline into the antecubital fossa and lies medial to the biceps tendon and brachial artery. It is rarely involved or injured as a result of elbow replacement. Because there are no branches of the median nerve to the arm, the first motor branches are to the pronator teres and flexor

15

carpi radialis, but they are remote and thus not typically encountered during routine approaches to the elbow joint (Fig. 2.11).

Musculocutaneous Nerve The cutaneous branch of this nerve emerges through the brachial fascia just at the lateral margin of the biceps tendon. It may rarely be entrapped here but more commonly is injured during anterior exposures of the joint.3 , 7

Radial Nerve The radial nerve courses laterally to occupy the groove in the humerus that bears its name, emerging anteriorly and laterally to penetrate the lateral intermuscular septum before entering the anterior aspect of the arm. It is here that it is especially vulnerable during revision cement removal or with the passage of cerclage wire to secure strut grafts. It gives off motor branches above the spiral groove to the medial head of the triceps muscle. This branch continues distally through the medial head to terminate as the muscular branch to the anconeus muscle (Fig. 2.12). This anatomic relationship allows surgical approaches that reflect the anconeus and still preserve the innervation of this muscle.4 , 11 , 20 In the antecubital space, the radial nerve penetrates the supinator muscle at the arcade of Frohse and continues distally into the forearm (Fig. 2.13). The radial nerve and posterior interosseous nerve are at risk of injury in this region, usually from retraction.16 , 25 They may also be compromised by excessive hemorrhage or synovial distension. Kamineni et al.10 have shown that the radial nerve penetration of the intermuscular septum occurs at a mean distance of 1.4 times the intercondylar distance (Fig. 2.14).

16

FIGURE 2.11 The median nerve innervates the flexor pronator muscle groups, but there are no branches above the elbow joint. (From Hollinshead WH: The back and limbs. In Anatomy for Surgeons, vol 3. New York, Harper & Row, 1969, p 379, with permission of Mayo Foundation.)

Ulnar Nerve The ulnar nerve is by far the most vulnerable nerve when dealing with reconstructive procedures about the elbow joint. The ulnar nerve appears in the distal humerus along the medial margin of the triceps muscle and accompanies the superior ulnar collateral branch of the brachial artery and the ulnar collateral branch of the ulnar artery. Because there are no significant motor branches of this nerve in the brachium, it is readily P.24

17

translocated or moved from its bed. In the distal humerus it passes into the cubital tunnel behind the medial epicondyle and under the cubital tunnel retinaculum21 to rest against the posterior aspect of the medial collateral ligament (Fig. 2.15). The close proximity of the ulnar nerve to the ulnar collateral ligament and medial capsule accounts, in part, for its vulnerability to nerve compression, entrapment, and stretch. Variably sized joint articular branches may be seen to emerge just proximal to the cubital tunnel or at the cubital tunnel, but the first motor branch to the flexor carpi ulnaris usually is 1 to 2 cm distal to the medial epicondyle. This may be sacrificed with impunity.

FIGURE 2.12 Continuation of the radial nerve into the anconeus explains the viability of this muscle when mobilized.

18

FIGURE 2.13 Muscles innervated by the radial nerve distal to the triceps. (From Hollinshead WH: The back and limbs. In Anatomy for Surgeons, vol 3. New York, Harper & Row, 1969, p 379, with permission of Mayo Foundation.)

19

FIGURE 2.14 The radial nerve emerges from posterior to anterior in the spiral groove and passes through the intramuscular septum proximal to the axis of rotation

20

at a distance 1.4 times the intercondylar dimension.

FIGURE 2.15 Ulnar nerve is vulnerable to injury with any elbow exposure; for this reason, decompression and transection are preferred by the author.

SURGICAL APPROACHES The “Family” of Posterior Exposures I have found virtually all reconstructive procedures can be done through a posterior skin incision. The elbow tolerates subcutaneous dissection through either the medial or the P.25

lateral aspects of the joint (Fig. 2.16). In this section, emphasis is placed on those exposures that are employed for elbow replacement. Of course, they may be adapted for the treatment of other conditions as well.6 , 14

Extensile Kocher Indications 21

The extensile Kocher11 approach may be used for joint arthroplasty, ankylosis, complex fractures of the distal humerus, synovectomy, radial head excision, and debridement for infection (Fig. 2.17). When performing an unlinked replacement, this is attractive since the joint can be hinged open and pivot on the intact medial collateral ligament. The lateral ligament is readily repaired at the conclusion of the case.

Description of Technique For joint replacement a posterior skin incision is employed, which passes just lateral to the top of the olecranon. The subcutaneous flap is elevated and the triceps is identified and freed from the brachioradialis and extensor carpi radialis longus along the posterior aspect of the lateral column (Fig. 2.17A) to the level of the joint capsule. The interval between the extensor carpi ulnaris and anconeus is identified distally and the interval is split proximally to the lateral epicondyle and proximally about 6 cm up the lateral column. The anconeus is reflected subperiosteally from the proximal ulna (Fig. 2.17B). Sharp dissection frees the bony attachment of the triceps expansion of the anconeus at the lateral epicondyle anteriorly. The extensor carpiulnaris is elevated distally, the common extensor is elevated from the epicondyle, and the extensor carpi radialis longus is released from the distal aspect of the anterior lateral column (Fig. 2.17C). After the subperiosteal release of the radial collateral ligament from the humerus, the joint may be dislocated with varus stress, providing generous exposure (Fig. 2.17D). We have found it necessary to replace about 50% of the triceps attachment to facilitate this maneuver.

22

FIGURE 2.16 Through a posterior skin incision (A) both medial (B) and lateral (C) deep intervals are accessible.

Mayo Modified Extensile Kocher The Mayo modification and extension of the Kocher17 , 18 extensile approach consists of reflecting the entire triceps insertion from the tip of the olecranon by sharp dissection, as with the Mayo approach (Fig. 2.18). In this way, the entire extensor mechanism may be reflected medially, allowing the elbow to be more readily opened with varus stress than is possible when the joint is tightly contracted.

Closure The triceps is reattached in a fashion identical to that described for the Mayo approach. The radial collateral ligament is reattached to the bone through holes placed in the lateral epicondyle.

Triceps Splitting Indications This approach is finding a resurgence of interest in recent years. The triceps-splitting approach5 is used for elbow arthroplasty, unreduced elbow dislocation, distal humeral fracture, posterior

23

P.26

exposure of the joint for ankylosis, sepsis, degenerative arthritis, and synovectomy. We prefer this for the multiple reoperated revision elbow especially when the triceps is already compromised or its attachment is absent (Fig. 2.19).

FIGURE 2.17 A: The extensile Kocher exposure is performed by an incision extended 8 cm proximal to the joint just posterior to the supracondylar bony ridge and distally over the anconeus for approximately 6 cm. B: The interval between the anconeus and the extensor carpi ulnaris is entered. C: The anconeus is reflected subperiosteally from the proximal ulna along with its fascial attachment to the triceps. The triceps is elevated from the humerus, the capsule is released posteriorly, and optionally the tip of the olecranon is removed. The common extensor tendon is released from the lateral epicondyle of the humerus as necessary to expose the capsule, which is entered with a longitudinal incision and released with a transverse incision. D: Release of the radial collateral ligament at its humeral origin allows the joint to sublux, exposing the entire distal humeral articulation. (From Morrey,17 by permission of Mayo Foundation.)

24

FIGURE 2.18 The Mayo modified extensile Kocher approach. The triceps attachment to the tip of the olecranon may be released by sharp dissection (A), allowing complete translation of the extensor mechanism medially and providing more extensile exposure to the joint (B). P.27

Description of Technique The skin incision begins in the midline over the triceps, approximately 10 cm proximal to the joint line, curves gently laterally or medially at the tip of the olecranon, and continues distally over the subcutaneous border of the proximal ulna for a distance of approximately 5 to 6 cm. If the incision is curved medially at the olecranon, the scar may have less tendency to contract.12 The triceps is exposed along with as much proximal ulna as dictated by the procedure. A midline incision is made through the triceps, fascia, and tendon down to bone and is continued distally across the insertion of the triceps tendon at the tip of the olecranon and down the subcutaneous crest of the ulna bone. The triceps tendon and muscle are retracted, exposing the distal humerus. The anconeus is then reflected subperiosteally laterally, while the flexor carpi ulnaris is similarly retracted medially. The insertion of the triceps is carefully

25

released from the olecranon, leaving the extensor mechanism in continuity with the forearm fascia and muscles medially and laterally. The ulnar nerve is visualized and protected in the cubital tunnel. Closure of the triceps fascia only is required proximally, but the insertion may be supplemented with a suture passed through the tip of the olecranon.

26

FIGURE 2.19 The original description of the Campbell posterior muscle-splitting approach calls for a curved incision, but we prefer a straight one just lateral to the tip of the olecranon and the subcutaneous border of the ulna. (From Anson BJ, McVaya CR: Surgical Anatomy, 5th ed, vol. 2. Philadelphia, WB Saunders, 1971, with permission.)

27

Mayo Posteromedial Exposure (Bryan, Morrey) Indications The Mayo posteromedial approach4 , 18 is used by the author for joint arthroplasty.

Description of Technique The author prefers the supine position, but the lateral decubitus may be used as well with a sandbag under the scapula. A nonsterile pneumatic tourniquet is applied high on the arm and the forearm is brought across the chest (Fig. 2.20). A straight posterior incision is made medial to the midline, approximately 10 cm proximal and 7 cm distal to the tip of the olecranon. The ulnar nerve is identified proximally in the epineural fat at the margin of the medial head of the triceps, and for joint replacement, it is carefully dissected free of the cubital tunnel to its first motor branch and brought into a subcutaneous pocket after removal of the intramuscular septum. P.28

The medial aspect of the triceps is elevated from the humerus and the posterior capsule is incised. The superficial fascia of the forearm is then incised distally off the ulna from medial to proximal ulna for about 6 cm. The periosteum and fascia complex is carefully reflected laterally. The extensor complex is thinnest and weakest just at its medial most attachment to the olecranon. Therefore, care must be exerted to maintain continuity of the triceps mechanism at this point. By placing tension on the elevated triceps proximally and on the ulnar fascia distally, the remaining portion of the attachment of the triceps mechanism is reflected by releasing the Sharpey fibers to the olecranon. The triceps attachment to the posterior lateral complex is released along with that of the anconeus. The anconeus is then subperiosteally elevated from its ulnar attachment. The entire extensor mechanism is then reflected lateral to the lateral epicondyle, thus widely exposing the entire joint. The radial head is exposed by incising the annular ligament.

28

FIGURE 2.20 The Bryan-Morrey posterior approach. A: A straight posterior skin incision (~14 cm) is made. B: The medial border of the triceps is identified and released, and the superficial forearm fascia is sharply incised to allow reflection of the fascia and periosteum from the proximal ulna. The ulnar nerve has been translocated anteriorly to subcutaneous tissue. C: The extensor mechanism is being reflected laterally, and the anconeus is being subperiosteally released from the ulna, allowing exposure of the radial head. The junction of the ulna, periosteum, and fascia with the insertion site of Sharpey fibers is the most tenuous portion of the reflected mechanism. The proximal olecranon is removed for joint exposure. D: The shoulder is externally rotated and the forearm is hyperflexed. Release of the collateral

29

ligaments allows the ulna to separate from the humerus, providing excellent exposure. The tip of the olecranon is removed for clear visualization of the trochlea. For joint replacement or interposition arthroplasty the ligaments are released medially and laterally from the humerus. This affords excellent exposure of the distal humerus and proximal ulna. In cases of semiconstrained joint replacement, repair of these ligaments is not necessary. If contracture or distortion is present, the flexor and/or extensor origins are also released. The triceps is returned to its anatomic position and sutured directly to the bone of the proximal end of the ulna (Fig. 2.21). The periosteum then is sutured to the superficial forearm fascia as far as the margin of the flexor carpi ulnaris. Note: A variation of this exposure releases the triceps with its osseous attachment as a wafer of bone instead of reflecting the tendon sharply from the ulna.26 P.29

30

FIGURE 2.21 Using a 2- to 3-mm drill bit, crossing osseous holes are placed in the olecranon emerging just off the subcutaneous border of the proximal ulna. A third transverse hole completes the preparation (A). A No. 5 nonabsorbable suture on a Keith needle is inserted from the distal medial through the proximal lateral hole. The triceps mechanism is grasped with an Alis clamp and brought back to its anatomic position. With the elbow at 90-degree flexion penetrate the triceps with the needle (B). A locked stitch allows the maintenance of the triceps securely over the olecranon. A second crisscrossed or locked suture is placed in the triceps tendon and the needle then enters the medial proximal hole and emerges from the lateral distal one (C). The stitch is then brought across the fascial tissue to tie at the medial margin of the ulna, a second transverse stitch is placed from medial to lateral across the ulna through the triceps attachment site of Sharpey fibers and then tied medially (D).

References 1. Anson BJ, McVaya CR: Surgical Anatomy, 5th ed, vol 2. Philadelphia, WB Saunders, 1971. 2. Atkinson WB, Elftman H: The carrying angle of the human arm as a secondary sex character. Anat Rec 91:46, 1945. 3. Banks SW, Laufman H: An Atlas of Surgical Exposures of the Extremities, 2nd ed. Philadelphia, WB Saunders, 1987.

31

4. Bryan RS, Morrey BF: Extensive posterior exposure of the elbow, a tricepssparing approach. Clin Orthop 166:188, 1982. 5. Campbell WC: Incision for exposure of the elbow joint. Am J Surg 15:65, 1932. 6. Ebraheim NA, Andreshak TG, Yeasting RA, et al: Posterior extensile approach to the elbow joint and distal humerus. Orthop Rev 22:578, 1993. 7. Eycleshymer AC, Schoemaker DM: A Cross-Section Anatomy. New York, D Appleton and Co., 1930. 8. Gardner E: The innervation of the elbow joint. Anat Rec 102:161, 1948. 9. Hollinshead WH: The back and limbs. In Anatomy for Surgeons, vol 3. New York, Harper & Row, 1969, p 379. 10. Kamineni S, Ankem H, Sanghavi S: A safe normalized parameter for lateral distal humeral pin insertion. Clin Anat 22:684-688, 2009. 11. Kocher T: Textbook of Operative Surgery, 3rd ed. London, A&C Black, 1911. Stiles HJ, Paul CB, translators. 12. Langman J, Woerdeman MW: Atlas of Medical Anatomy. Philadelphia, WB Saunders, 1976. 13. Lanz T, Wachsmuth W: Praktische Anatomie. Berlin, ARM, Springer-Verlag, 1959. 14. MacAusland WR: Ankylosis of the elbow: With report of four cases treated by arthroplasty. JAMA 64:312, 1915. 15. Martin BF: The annular ligament of the superior radial ulnar joint. J Anat 52:473, 1956. 16. Morrey BF: Applied anatomy and biomechanics of the elbow joint. Instr Course 35:59, 1986. 17. Morrey BF (Editor and contributing author): The Elbow and its Disorders, 3rd ed. Philadelphia, W.B. Saunders Company, 2000. 18. Morrey BF: Elbow exposures. In Morrey BF (ed): Master Techniques in Orthopaedic Surgery: The Elbow. New York, Raven Press, 1994, p 59. 19. Morrey BF, An KN: Functional anatomy of the ligaments of the elbow. Clin Orthop 201:84-90, 1985. 20. Morrey BF, Schneeberger A: Anconeus arthroplasty. Am J Bone Joint Surg 84a:1960, 2002. P.30

32

21. O'Driscoll SW, Horii E, Carmichael SW, Morrey BF: The cubital tunnel and ulnar neuropathy. J Bone Joint Surg 73B:613, 1991. 22. O'Driscoll SW, Bell DF, Morrey BF: Posterolateral rotatory instability of the elbow. J Bone Joint Surg 73A(3):440-446, 1991. 23. Schwab GH, Bennett JB, Woods GW, Tullos HS: The biomechanics of elbow stability, the role of the medial collateral ligament. Clin Orthop 146:42, 1980. 24. Wevers HW, Siu DW, Brookhoven LH, Sorbie C: Resurfacing elbow prosthesis: shape and sizing of the humerus component. J Biomech Surg 7:241, 1985. 25. Witt JD, Kamineni S: The posterior interosseous nerve and the posterolateral appraoch to the proximal radius. J Bone Joint Surg 80B(2):240-242, 1998. 26. Wolfe SW, Ranawat CS: The osteo-anconeus flap: An approach for total elbow arthroplasty. J Bone Joint Surg 72A:684, 1990. 27. Yamaguchi K, Sweet FA, Bindra R, et al: The extraosseous and intraosseous arterial anatomy of the adult elbow. J Bone Joint Surg 79A:1653-1662, 1997.

33

Chapter 3 Relevant Biomechanics Kai-Nan An Bernard F. Morrey As with any joint reconstructive procedure, a clear and detailed understanding of the relevant biomechanics of the joint is essential. This understanding may be simplified if the discussion is arbitrarily divided into the main joint functions: motion, stability (constraints), and strength (forces)19 discussed in the context of joint reconstructive surgery.

MOTION The elbow is classified as a trochleoginglymoid joint; that is, it has two degrees of freedom: flexion-extension and axial rotation. Technically, this motion is considered both rolling and spinning.

Characteristics Axis of Rotation The axis of rotation of flexion-extension has been defined as occurring about a tight locus of points measuring only 2 to 3 mm in the broadest dimension (Fig. 3.1).27 This locus is positioned at the center of the projected center of the trochlea and at the center of the capitellum.18 This is one of the most important features of the biomechanics of this joint, because replication of this axis is essential for the proper balancing of soft tissue, particularly necessary in unlinked joint replacement,7 , 9 distraction arthroplasty,20 and ligament reconstruction28 and for optimum strength after replacement.24 The value of accurate replication of the axis is also being more clear as a means of avoiding bushing wear of linked devices as well.17

1

FIGURE 3.1 Very small locus of instant center of rotation for the elbow joint may be replicated by a single line drawn from the inferior aspect of the medial epicondyle through the center of the lateral epicondyle, which is in the center of the lateral projected curvature of the trochlea and capitellum.

Carrying Angle The carrying angle of the elbow joint is replicated by all joint replacement implants by angular changes at the humerus, the ulna, or both (Fig. 3.2). Any of these design approaches may be considered biomechanically sound.2 , 8 This characteristic is of importance primarily to balance the collateral ligaments in resurfacing joint replacement and to ensure that the forces across the articulation are balanced from a varus/valgus prospective.

Functional Motion Although the elbow has a normal arc of flexion-extension of 0 to 150/160 degrees and pronation-supination of 75 to 85 degrees,5 the full arc of motion is not generally used for most activities of daily living. Most such activities can be carried out with an arc of motion of 30 to 130 degrees of flexion-extension (Fig. 3.3) and by 50 degrees of pronation and 50 degrees of supination.25 P.32

2

FIGURE 3.2 The carrying angle is defined by the combination of humeral and ulnar articulation tilt. Dominance of the humeral (A) or ulnar (B) angle affects the kinematics, especially carrying angle change with flexion.

3

FIGURE 3.3 Functional arc of elbow motion for activities of daily living is approximately 100 degrees (between 30 and 103 degrees). (Adapted from Morrey BF, Askew LJ, An KN, Chao EY: A biomechanical study of functional elbow motion. J Bone Joint Surg 63A: 872, 1981, with permission.)

CONSTRAINTS Understanding the constraints of the elbow is simplified by dividing these elements into static and dynamic contributions. The static contribution to elbow stability is further subdivided into articular and ligamentous capsular features. In general, it may be concluded that the articular and ligamentous components to joint stability are about equally divided.21 The articular contribution is further subdivided into the radiohumeral and ulnohumeral joints.

Static Constraints Articular Contribution: Radiohumeral Joint The three-dimensional displacement characteristics of the elbow following medial collateral ligament (MCL) and radial head removal have been studied with a magnetic fieldgenerating telemetry system.1

4

When the radial head is removed first, virtually no change in valgus or axial stability of the joint is demonstrated.23 However, when the MCL is removed, the elbow becomes unstable and subluxes. Conversely, when the anterior bundle of the MCL is removed first, a modest but definite and consistent instability to valgus and axial rotation is present (Fig. 3.4). However, with subsequent removal of the radial head, dramatic instability ensues. The interpretation leaves one to conclude that the radial head should be considered a secondary stabilizer of the joint. The implications are obvious: the radial head must be preserved or its function replicated if there is MCL dysfunction. Of note, radial head replacement by any one of several designs is not totally adequate to restore valgus stability of the normal elbow (Fig. 3.5).16 , 31 The kinematics and stability of the elbow joint after elbow replacement have been evaluated using the same model. The motion pattern depends on the articular geometry of the implant and the compressive force across the joint. The maximum valgus/varus laxity is 6.5, 6.4 and 10.8 degrees for the Souter-Strathclyde, the capitellocondylar, and the Coonrad-Morrey prosthesis, respectively (Fig. 3.6).

Ulnohumeral Joint The elbow joint is one of the most congruent joints of the body. The contact area of the ulna with respect to the trochlea may be considered to consist of two anterior and two posterior articulating surfaces on the coronoid and olecranon, respectively (Fig. 3.7).12 , 13 , 35 If the ligaments are intact, loss of the olecranon is unimportant for stability,3 but loss of the coronoid obviously allows posterior ulnar displacement that is difficult or impossible to reconstruct effectively.32

Ligaments The anatomy of the MCL and lateral collateral ligament (LCL) complexes has been discussed in detail in Chapter 2. The origin of the anterior bundle of the medial ulnar collateral ligament coincides with the axis of flexion as does the lateral collateral complex. Hence, both are functional throughout P.33

the arc of flexion and serve as “guy wires” to stabilize the ulnohumeral

5

joint (Fig. 3.8). The anterior bundle of the ulnar collateral ligament has been shown to be the prime valgus stabilizer of the elbow.11 , 34 The lateral ulnar collateral ligament has been demonstrated to play a similar role in varus and rotatory stability of the joint.29 Advanced measurement techniques also have been used to study the role of soft tissue constraints after semiconstrained arthroplasty. The typical motion pattern is within the balance of the articulation, implying that the out-of-plane forces are absorbed by soft tissue constraints before being transmitted to the bone-cement interface30 (Fig. 3.9). Sectioning of the LCL or the MCL significantly increased the joint laxity of the elbow joint after implant replacement (Fig. 3.10).

FIGURE 3.4 Diagrammatic representation demonstrating that the radial head is a secondary stabilizer to the elbow in valgus stress, whereas the MCL should be considered a primary stabilizer.

6

FIGURE 3.5 Obvious gross instability when the radial head is absent. Note only partial improvement with any of the studied radial head designs.

FIGURE 3.6 Note that varus/valgus laxity of linked implants more closely replicate normal varus/valgus laxity.

7

FIGURE 3.7 Contact of the ulnohumeral joint with varus and valgus loads and the elbow at 90 degrees. Notice only minimal radiohumeral contact in this loading condition. (From Stormont TJ, An KN, Morrey BF, Chao EY: Elbow joint contact study: comparison of techniques. J Biomech 18:329, 1985, with permission.)

8

FIGURE 3.8 The origin of anterior components of both the MCL and the LCLs is at the axis of rotation of the joint.

9

FIGURE 3.9 Semiconstrained Mayo-modified Coonrad implant demonstrates an amplitude of varus-valgus rotation during elbow flexion that is less than that provided by the articulation. This suggests that the soft tissue partially stabilizes the implant. P.34

FIGURE 3.10 The motion patterns of the capitellocondylar elbow prostheses after later collateral ligament sectioning. A: The motion after arthroplasty with the ligament still intact; B: after sectioning MCL. The elbow became markedly unstable with valgus loading; C: further sectioning LCL. Gross varus instability occurred after the lateral ulnar and radial collateral ligaments were removed. (From King GJW, Itoi E, Niebur GL, et al: Motion and laxity of the capitellocondylar total elbow prosthesis. J Bone Joint Surg 76[A]:1000-1008, 1994, with permission.)

Dynamic Effect Few studies have been done on the dynamic stabilizers of the elbow. The flexor and extensor motors tend to posteriorly displace the ulnohumeral joint, but they do provide a slight varus/valgus stabilizing effect.10 , 23 The overall dynamic effect of the flexors and extensors is

10

well-known to posteriorly displace the forearm referable to the humerus throughout the arc of flexion. It is for this reason that unlinked implants tend to dislocate. Fractures of the coronoid also demonstrate this dynamic effect, with the tendency for posterior displacement of the ulna referable to the humerus especially noted at 90 degrees. As is logical and anticipated, active pronation also stabilizes the lateral ligament, resisting rotatory and varus displacement.6

JOINT FORCES Radiohumeral Joint Static axial load of the extended joint has revealed that about 40% of forces are transmitted through the radiohumeral joint and 60% through the ulnohumeral articulation.13 , 14 , 36 and that the absolute force through the radial head exceeds several times body weight22 (Fig. 3.11). The force transmission across the radiohumeral joint also decreases in supination and increases in pronation (Fig. 3.12). This is due to a screw-home mechanism of the radius with respect to the ulna,22 with slight proximal migration occurring in pronation and slight distal translation occurring in supination. This observation is important in designing rehabilitation programs that protect the radiohumeral joint for such conditions as osteochondritis dissecans and after radial head fracture and also for prosthetic replacement design.26

11

FIGURE 3.11 In extension axial load transmits approximately 60% force across the radiohumeral joint; 40% is transmitted across the ulnohumeral joint. P.35

12

FIGURE 3.12 During all flexion angles of the elbow, pronation is associated with greater force transmission across the radiohumeral joint than is supination. (Modified from Morrey BF, An KN: Articular ligamentous contributions to the stability of the elbow joint. Am J Sports Med 11:315, 1983, with permission.)

Ulnohumeral Joint The force across a joint is dependent on the efficiency of the muscles that are recruited for the activity. For the elbow, the least efficiency is in extension (the shortest moment arm) and the greatest efficiency is at 90 degrees of flexion (Fig. 3.13). When lifting weight, the maximum flexion strengths for an average normal person range from 100 N with the elbow in the extended position to 400 N with the elbow at the 90degree flexed position.4 , 15 The placement of the implant could

13

influence the kinematics and the muscle moment arms of the elbow joint and eventually, the joint forces.33

FIGURE 3.13 The mechanical advantage of elbow flexors changes depending on the position of the forearm. As the lever arm increases at 90 degrees of flexion, greater torque can be generated even though the resultant force across the elbow does not increase. Calculations under these loading conditions suggest that the resultant joint force through the ulnohumeral joint can range from one to three times body weight (Fig. 3.14). When the elbow is in the extended position, the resultant joint force points proximally and anteriorly. When the elbow is in a more flexed position, the resultant force points posteriorly and proximally. The cyclic, high-grade load applied to the elbow justifies consideration of the elbow as a weight-bearing joint and further accounts for the high loosening rate seen in the early constrained joints in which motion transmitted across the articulation was directed to the bone-cement interface (Fig. 3.15).

14

FIGURE 3.14 Under strenuous lifting of weight in the hand, up to three times body weight can be transmitted across the elbow joint. The direction of these resultant forces changes with joint angle. P.36

15

FIGURE 3.15 Typical loosening pattern of all implant designs both unlinked (A) and linked (B) with the tip of the prosthesis eroding superiorly and anteriorly through the humerus.

DESIGN CONSIDERATIONS Based on the above review of the anatomy of the biomechanics of the joint, the optimum elbow joint should be adequately designed so that it can be reliably implanted in a manner to replicate the axis of rotation. The surgical technique should be planned to preserve as much as possible of the soft tissue ligamentous constraints; if violated, these must be anatomically repaired when using the unlinked options. Anatomic placement of the axis of rotation provides the proper mechanical advantage of flexors and extensors that allows the patient to have the best possible restoration of strength function. The intramedullary stem fixation is probably not adequate to resist the stresses imparted to the system. A supplementary flange placed in the distal aspect of the humerus has been demonstrated to resist the adverse effects of the posterosuperior force as the elbow initiates and completes the flexion movement (Fig. 3.16). In addition, this design characteristic resists axial rotation of the implant as well, thus lessening the overall complication rate of loosening. This has proven to

16

be effective in current designs. It has also been noted that the flange assists in aligning the implant to replicate the flexion axis in settings in which the distal humerus is absent (Fig. 3.17).

FIGURE 3.16 A flange with bone graft theoretically resists posterior forces.

17

FIGURE 3.17 The flange has proven effective in finite element analysis as the flange is used to both align the axis and resist posterior and torsional forces.

References 1. An KN, Jacobsen MC, Berglund LJ, Chao EYS: Application of a magnetic tracking device to kinesiologic studies. J Biomech 21:613, 1988. 2. An KN, Morrey BF, Chao EYS: Carrying angle of the human elbow joint. J Orthop Res 1:369, 1984. 3. An KN, Morrey BF, Chao EYS: The effect of partial removal of the proximal ulna on elbow constraint. Clin Orthop 209:270, 1986. 4. Askew LJ, An KN, Morrey BF, Chao EYS: Isometric elbow strength in normal individuals. Clin Orthop 222:261, 1987. P.37

5. Boone DC, Azen SP: Normal range of motion of joints in male subjects. J Bone Joint Surg 61A:756, 1979.

18

6. Dunning CE, Zarzour ZD, Patterson SD, et al: Muscle forces and pronation stabilize the lateral ligament deficient elbow. Clin Orthop 388:118-124, 2001. 7. Evans GB, Daniels AU, Serbousek JC, Mann RJ: A comparison of the mechanical designs of articulating total elbow prostheses. Clin Mater 3:235, 1988. 8. Figgie HE III, Inglis AE, Gordan NH, et al: A critical analysis of mechanical factors correlated with bone remodeling following total elbow arthroplasty. J Arthroplasty 1:175, 1986. 9. Figgie HE III, Inglis AE, Mow C: A critical analysis of alignment factors affecting functional outcome in total elbow arthroplasty. J Arthroplasty 1:169, 1986. 10. Funk DA, An KN, Morrey BF, Daube JR: Electromyographic analysis of muscles across the elbow joint. J Orthop Res 5:529, 1987. 11. Fuss FK: The ulnar collateral ligament of the human elbow joint: Anatomy, function and biomechanics. J Anat 175:203, 1991. 12. Goel VK, Smith D, Bijlani V: Contact areas in human elbow joints. J Biomech 104:169, 1982. 13. Hall AA, Travill R: Transmission of pressures across the elbow joint. Anat Rec 150:243, 1964. 14. Hotchkiss RN, An KN, Sowa DT, et al: An anatomic and mechanical study of the interosseous membrane of the forearm: Pathomechanics of proximal migration of the radius. J Hand Surg 14:256, 1989 15. Jorgensen K, Bankov S: Maximum strength of elbow flexors with pronated supinated forearm. Med Sport Biomech 6:174, 1971. 16. King GJW, Itoi E, Niebur GL, et al: Motion and laxity of the capitellocondylar total elbow prosthesis. J Bone Joint Surg 76[A]:10001008, 1994. 17. Lee BP, Adams RA, Morrey BF. Polyethylene wear after total elbow arthroplasty. J Bone Joint Surg 87A(5):1080-1087, 2005. 18. London JT: Kinematics of the elbow. J Bone Joint Surg 63A:529, 1981. 19. Morrey BF: Applied anatomy and biomechanics of the elbow joint. Instr Course Lect 35:59, 1986. 20. Morrey BF: Posttraumatic contracture of the elbow: Operative treatment including distraction arthroplasty. J Bone Joint Surg 72A:601, 1990.

19

21. Morrey BF, An KN: Articular ligamentous contributions to the stability of the elbow joint. Am J Sports Med 11:315, 1983. 22. Morrey BF, An KN, Stormont TJ: Force transmission through the radial head. J Bone Joint Surg 70A: 2:250, 1988. 23. Morrey BF, An KN, Tanaka S: Valgus stability of the elbow: A definition of primary and secondary constraints. Clin Orthop 265:187, 1991. 24. Morrey BF, Askew LJ, An KN: Strength function after elbow arthroplasty. Clin Orthop 234:43, 1988. 25. Morrey BF, Askew LJ, An KN, Chao EY: A biomechanical study of functional elbow motion. J Bone Joint Surg 63A: 872, 1981. 26. Morrey BF, Askew LJ, Chao EY: Silastic prosthetic replacement of the radial head. J Bone Joint Surg 63A:454, 1981. 27. Morrey BF, Chao EY: Passive motion of the elbow joint. J Bone Joint Surg 58A:501, 1976. 28. Nestor BJ, O'Driscoll SW, Morrey BF: Ligamentous reconstruction for posterolateral rotatory instability of the elbow. J Bone Joint Surg 74A:1235, 1992. 29. O'Driscoll SW, Bell DF, Morrey BF: Posterolateral rotatory instability of the elbow. J Bone Joint Surg 73A:440, 1991. 30. O'Driscoll SW, Tanaka S, An KN, Morrey BF: The kinematics of the semiconstrained total elbow prosthesis. J Bone Joint Surg 74B:297, 1992. 31. Pomianowski S, Morrey BF, Neale PG, et al: Contribution of monoblock and bipolar radial head prostheses to valgus stability of the elbow. J Bone Joint 83A(12):1829-1834, 2001. 32. Regan W, Morrey BF: Fractures of the coronoid process of the ulna. J Bone Joint Surg 71A:1348, 1989. 33. Schuind F, O'Driscoll SW, Korinek S, et al: Changes of elbow muscle moment arms after total elbow arthroplasty. J Shoulder Elbow Surg 3: 191-199, 1994. 34. Schwab GH, Bennett JB, Woods GW, Tullos HS: Biomechanics of elbow instability: The role of the medial collateral ligament. Clin Orthop 146:42, 1980. 35. Stormont TJ, An KN, Morrey BF, Chao EY: Elbow joint contact study: Comparison of techniques. J Biomech 18:329, 1985.

20

36. Walker PS: Human Joints and Their Artificial Replacements. Springfield, Charles C Thomas, 1977, p 182.

21

Chapter 4 Radial Head Replacement Joaquin Sanchez-Sotelo The radial head plays an important role in the stability and function of the elbow and forearm. Pain and other symptoms may result from involvement of the radial head by injuries, inflammatory arthropathies, or degenerative conditions. Resection of the radial head has been used with some success for isolated (simple or uncomplicated) radial head fractures14 or as part of joint debridement procedures in rheumatoid arthritis.8 However, radial head resection may contribute to unsatisfactory results when performed in the setting of complex elbow instability30 or longitudinal instability of the radius.5 Replacement arthroplasty is considered in these and other situations when the native radial head cannot be preserved. Radial head replacement has been used for a long time. The first article in the English literature about the use of a radial head implant was published by Speed37 in 1941, who reported implantation of a vitallium prosthesis in three patients. Radial head arthroplasty was popularized by Swanson39 with the introduction of a silicone implant, but silicone synovitis led to abandonment of silicone radial heads.44 Improved understanding of the anatomy of the radial head and neck3 , 20 , 40 , 42 and advances in prosthesis materials and designs have prompted the introduction of multiple modern radial head implants, which are being increasingly used. However, the ideal design features, fixation method, implant alignment, and long-term effects on the articular cartilage of the capitellum remain largely unknown.

DESIGN AND FIXATION Modern radial head implants are modular, allowing combination of different head and stem sizes, and the possibility of implantation of the head after the stem has been seated, which may be useful especially when implanted through more limited exposures. Most prosthetic heads are made of a cobalt-chrome or titanium alloy, although there are some all-polyethylene and pyrolytic carbon implants. The stems may be fixed with or without acrylic cement, and the stem-head junction may be fixed or bipolar (Fig. 4.1).

1

Prosthetic Head Shape and Sizing Most prosthetic radial heads are round with a shallow superior concavity. Currently, there is only one design with truly anatomic heads, which are asymmetric to replicate the shape of the native head; the clinical implications of using an anatomic versus an almost anatomic radial head are unknown. Selection of the correct head size for each individual is extremely important. The prosthetic head diameter is usually selected based on the size of the resected radial head when available; otherwise, diameter selection may be based on measurements performed on radiographs of the opposite elbow and intraoperative assessments. The height of the prosthetic head is critical to restore the adequate length of the radius. Some systems provide very limited options, especially when the head of the implant is proportional to its diameter and a limited number of sizes are provided. Ideally, the thickness of the implant should be selected independently of the head diameter to allow accurate radius length restoration for different fracture patterns and resection levels. This goal may be achieved by either manufacturing heads with several heights for each diameter or using stems with several neck lengths. Metallic radial heads provide superior mechanical properties than the old silicone implants and have been proven to restore the function of the native radial head in terms of elbow stability.10 , 16 , 21 However, the long-term effects of a metallic implant on the cartilage of the capitellum are unknown, and severe cartilage loss has been reported.43 Allpolyethylene implants may be less detrimental in terms of cartilage erosion, but they introduce the possibility of particulate debris. Pyrolytic carbon implants have been used mostly in finger joint arthroplasty and may lead to decreased cartilage wear, but the experience with pyrolytic carbon radial head implants is very limited.

Stem Fixation Radial head implants may be fixed with or without polymethylmethacrylate (Table 4.1). Cementless implants are attractive, as the proximal radius provides little room for cement and if cemented implants fail, cement removal may lead to bone loss. There are smooth and textured cementless stems. A high incidence of

2

radiolucent lines has been reported with smooth cementless stems.24 At midterm follow-up, these radiographic changes do not seem to be associated with symptoms, but they nonetheless indicate radiographic loosening and are a reason for concern. Proponents of smooth cementless stems state that use of a somewhat loose stem allows selfcentering of the head implant on the capitellum with range of motion. These implants are thus more forgiving, do not require accurate preparation of the radius canal or a very tight fit, and may obviate the need of a bipolar design. However, the long-term implications of associated radiolucencies are still unknown. Textured cementless stems are attractive, as they follow the principles of cementless stem fixation in other joints such as the hip or shoulder. The main concerns with these types of implants include the difficulty in achieving accurate preparation of such a small canal with some risk for intraoperative fractures, as well as the potential for stress shielding with bone resorption under the prosthetic head and potential for bone loss if a well-fixed implant needs to be removed. Use of a textured cementless stem or a cemented stem requires adequate understanding of the ideal position of the implant, as it will not allow the selfcentering of smooth cementless stems unless matched with a bipolar head. The stem length for most systems is very similar, with the tip of the prosthesis usually ending at the level of the bicipital tuberosity. The Judet bipolar radial head replacement has a much longer stem, which may be useful in the revision setting but may be too invasive for primary use. P.39

3

FIGURE 4.1 Most modern implants are metallic and modular. A: The Evolve prosthesis is characterized by a smooth polished stem, two neck lengths, and multiple heights and diameters. B: The Acumed prosthesis is designed for ingrowth fixation and provides multiple neck lengths and an anatomic design. C: The Judet prosthesis is the classic example of a bipolar implant.

Fixed and Bipolar Designs Satisfactory tracking of a radial head implant on the capitellum may be difficult to achieve, especially in chronic situations where the alignment of the proximal radius may be distorted.47 Bipolar implants are attractive in these circumstances, as motion between the head and the stem allows tilting and self-centering of the prosthetic head, potentially improving tracking. An in vitro study found better ability to resist elbow subluxation in the presence of a 50% coronoid defect when

4

P.40

a bipolar implant was compared with a fixed implant.47 The main concerns with bipolar implants include the possibility of decreased elbow stability if implant tilt facilitates subluxation and the generation of polyethylene debris at the bipolar articulation. One study found increased elbow valgus laxity in neutral forearm rotation in the medial collateral ligament deficient elbow when the Judet bipolar implant was compared with a fixed design.26 A recent study of 51 Judet bipolar radial head replacements reported progressive osteolysis in 37 elbows (73%) at an average follow-up time of 8.4 years.28

TABLE 4.1 ADVANTAGES AND DISADVANTAGES OF CEMENTED AND CEMENTLESS FIXATION

Cemented

Cementless

Advantages

  

Predictable fixation Easier canal preparation May be cemented slightly proud if needed to restore adequate radial length





Some smooth implants self-center on the capitellum with range of motion Cement removal not needed if revision becomes necessary

Disadvantages



Cement removal may lead to bone loss if revision becomes necessary

 



Less predictable fixation Canal preparation for true press-fit fixation is difficult Revision of textured well-fixed implants may lead to bone loss

5

INDICATIONS Radial Head Fractures The most popular indication for implantation of radial head prostheses is the acute irreconstructible radial head fracture. Internal fixation is accepted as the treatment of choice for displaced radial head fractures when possible.29 , 31 However, internal fixation may not be technically possible for severely comminuted fractures, and poor results have been reported with internal fixation in fractures with more than three fragments.31 Resection of the irreconstructible radial head may provide reasonable longterm results in the absence of associated injuries.13 The function of the radial head becomes more critical in the presence of large coronoid fractures or disruption of the elbow collateral ligaments or interosseous membrane, and radial head resection in these circumstances may contribute to a poor result.13 , 30 Radial head replacement provides better results for these complex irreconstructible radial head fractures5 , 6 , 29 (Table 4.2). The use of radial head replacement for isolated irreconstructible radial head fractures is still controversial. I believe it will be more accepted as satisfactory long-term survival of modern designs is confirmed. The potential benefits of avoiding progressive valgus angulation and decreasing the loads on the ulnohumeral joint cartilage need to be balanced against the potential for progressive capitellum cartilage erosion, implant-related complications, and the need to avoid activities imposing heavy demands on the elbow joint.

TABLE 4.2 INDICATIONS FOR RADIAL HEAD REPLACEMENT

6

Acute irreconstructible radial head fractures

Complex (associated injuries)

Elbow fracture-dislocation

Medial collateral ligament disruption

Lateral collateral ligament complex disruption

Coronoid fracture

Longitudinal instability of the radius (Essex-Lopresti injury)

Simple (isolated radial head fracture)—controversial

Chronic conditions

Radial head nonunion, malunion, or posttraumatic osteoarthritis

After radial head resection

Elbow instability

Chronic Essex-Lopresti injury

Proximal radioulnar impingement

Radial head dislocation

7

Old Monteggia fracture-dislocation

Congenital (controversial)

Proximal radioulnar synostosis

Reconstruction in Chronic Conditions Radial head replacement may also be indicated in several chronic conditions. Nonunion or malunion may complicate radial head fractures after nonoperative treatment or internal fixation; pain and limited motion secondary to these two conditions may be improved with resection or replacement. The decision to perform one or the other is based on associated symptoms and pathology, age, anticipated demands, and surgeon preferences. Posttraumatic osteoarthritis affecting mostly the lateral compartment of the elbow may also benefit from radial head replacement when the radial head is deformed and arthritic. Replacement is also considered in patients with a previous radial head resection and symptoms of elbow instability, wrist pain, or proximal radioulnar impingement. Restoration of elbow stability after trauma often requires reconstruction of the lateral collateral ligament complex; replacement of a previously resected radial head may help restore stability by providing more articular constraint and increasing the tension on the collateral reconstruction. Radial head replacement may also be indicated in patients with wrist pain secondary to proximal migration of the radius or pain in the proximal third of the forearm secondary to impingement between the proximal radius stump and the lateral cortex of the ulna.

8

Radial head dislocation represents a less common and more controversial indication for radial head replacement. Replacement in congenital head dislocation is challenging, as the capitellum is oftentimes dysplastic and proper alignment and tracking are difficult to restore. Replacement may be needed in the treatment of Monteggiatype injuries if the radial head was fractured or develops erosion or degenerative changes; correction of residual ulnar malalignment is needed to restore adequate alignment and tracking of the replaced radial head. Proximal radioulnar synostosis may be treated by either resection of the ectopic bone or creation of a pseudoarthrosis distal to the area of synostosis (reverse Sauve-Kapandji procedure);18 en bloc removal of the ectopic bone and radial head followed by replacement may be considered in selected cases with extensive involvement. The cartilage of the capitellum may be damaged when radial head replacement is considered in any of these P.41

chronic conditions. Consideration should be given in those circumstances to a combined replacement of the capitellum and the radial head (lateral unicompartmental elbow arthroplasty) if the severity of the capitellar cartilage damage is considered to be a potential cause for ongoing pain or if the amount of capitellar bone loss prevents adequate tracking and stability. When radial head resection without replacement is considered, the elbow and forearm should be tested for instability. Valgus and posterolateral rotatory instabilities are best detected under anesthesia and fluoroscopy. Axial forearm instability may be detected using the radius pull test, considered positive if the neck of the radius abuts the capitellum or if there is more than 5 mm change in ulnar variance at the wrist.36

SURGICAL TECHNIQUE Exposure Exposure for radial head replacement is selected based on the presence of associated pathology. The procedure may be performed through a relatively limited approach when no additional surgical gestures are required (isolated radial head fracture, nonunion,

9

malunion, or arthritis). At our institution, the so-called Kaplan approach is used in most of these circumstances.19 In this approach, the extensor carpi radialis brevis (ECRB) is split in line with Lister tubercle (Fig. 4.2). Incision of the annular ligament underneath the ECRB provides access to the radial head, and the supinator muscle can be elevated from proximal to distal if the radial neck needs to be exposed. Care should be taken to protect the posterior interosseous nerve; placing the forearm in pronation displaces this nerve distally and allows safe exposure of at least 35 mm of proximal radius. A retractor placed around the neck may be used to lever the radial head and neck anteriorly for fixation or replacement. Release of the lateral collateral ligament off the humeral epicondyle may be performed to increase exposure in very large individuals, but it is rarely needed.

10

FIGURE 4.2 The so-called Kaplan approach is ideally suited for isolated radial head replacement. A: Skin incision. B: Exposed fracture of the radial head through the extensor split. More commonly, radial head replacement is considered in the setting of complex elbow trauma. The lateral collateral ligament complex is

11

disrupted in elbow fracture-dislocations, providing an excellent exposure for radial head replacement through Köcher interval (Fig. 4.3). The same interval is also ideal in chronic conditions with insufficiency of the lateral collateral ligament complex requiring reconstruction. Transolecranon fracture-dislocations may allow radial head replacement through the olecranon fracture, although some authors prefer adding a small separate lateral approach. We have no experience with exposure through a posterior osteotomy of the ulnar supinator tuberosity.38

Canal Preparation Preparation of the radial canal is relatively straight forward. After removal of the native radial head, the medullary canal is easily identified and most systems offer a set of broaches to create room for the prosthetic stem (Fig. 4.4A). Cemented and polished cemented stems do not require accurate fitting of the last broach used or the real stem. Aggressive broaching should be avoided especially when cement is planned to be used. On the contrary, a tight fit is recommended with cementless stems designed for ingrowth fixation.

Sizing, Alignment and Tracking This is the most critical step of the whole surgical procedure. A poorly sized or malaligned prosthesis may facilitate instability or progressive joint degeneration. The most common P.42

mistake is to use an excessively thick implant, which will lead to radius overlengthening (joint “overstuffing”), with the potential for increased pressure on the articular cartilage of the capitellum and poor tracking. Experimental data suggest altered elbow kinematics with as little as 2.5 mm of overlengthening or underlengthening.41 It is important to remember that the prosthetic implant replaces both bone and cartilage and its radiographic appearance will be slightly larger than the native radial head.

12

FIGURE 4.3 In elbow fracture-dislocations, the lateral collateral ligament complex is usually avulsed from the lateral epicondyle (forceps), and the radial head is exposed through Kocher interval.

13

FIGURE 4.4 Basic steps for implantation of a radial head replacement. A: Canal broaching. B, C: Diameter and height selection are based on the resected radial head. D: Intraoperative radiographs help confirm restoration of adequate radial length. E: Trials. The diameter of the radial head implant should be based, whenever possible, on the diameter of the resected radial head, unless deficient or severely deformed. The height of the radial head is selected to replicate the native length of the radius (Fig. 4.4B,C). Some systems offer very limited height options, with a height proportional to the head

14

diameter. Other systems offer several head heights for each diameter, stems with different neck lengths, or adjustable necks. Several parameters may be used intraoperatively to judge the adequacy of the head height (Table 4.3). The center of the superior concavity of the implant should be at the same height as the lateral aspect of the coronoid. In addition, the lateral ulnohumeral joint should remain congruent. Some systems offer filler gauges to determine which thickness will allow contact of the radial head with the capitellum without opening the lateral ulnohumeral joint line space. P.43

Intraoperative radiographs or fluoroscopy may be used to confirm the symmetry of the ulnohumeral joint: opening of the lateral joint line with closing of the medial joint line is consistent with overlengthening (Fig. 4.4D), although comparison with radiographs of the opposite elbow may be more accurate.32

TABLE 4.3 REFERENCE PARAMETERS TO AVOID RADIAL OVERLENGTHENING AND SELECT THE CORRECT HEAD SIZE

Head diameter

Diameter of the resected native radial head

Intraoperative fluoroscopy shows adequate dimensions

Head height

Concavity of the implant flush with the lateral margin of the coronoid

The lateral ulnohumeral joint line remains congruent

Intraoperative use of filler gauges

15

Intraoperative AP fluoroscopy (symmetric medial and lateral joint lines)

Ulnohumeral joint symmetry compared to the opposite elbow

Once the correct size and height are selected, the corresponding trial implant should be used to confirm adequate tracking with flexion, extension, pronation, and supination (Fig. 4.4E). Poor tracking may be secondary to incorrect sizing, poor implant design, uncorrected pathology, or malalignment of the implant respective to the proximal radius. Resection of a few millimeters of radial neck may facilitate implant tracking. The plane of resection should be perpendicular to the axis of forearm rotation, a line connecting the center of the capitellum proximally with the ulnar styloid distally, and some systems provide a guide to confirm this orientation (Fig. 4.5). Some systems also offer calcar reamers, which ensure correct orientation of the base of the head implant with the position of the stem. When adequate tracking cannot be achieved despite correct sizing, alignment, and removal of interposed fibrous tissue, consideration should be given to the use of a bipolar arthroplasty or alternative reconstructive procedures such as radiocapitellar hemiarthroplasty25 or anconeus interposition arthroplasty.12

Implant Insertion Most current implants are modular, allowing separate insertion of the stem and the head if preferred. However, we usually assemble the stem and the head on a back table and insert the head and stem together. When cemented fixation is selected, we prefer to use a limited amount

16

of cement and plug the canal to avoid cement migration distally. Care must be taken when implanting true press-fit stems, as the radial neck may fracture during insertion of the real implant.

FIGURE 4.5 Some systems provide guides to check the orientation of the radial neck.

Closure Repair or reconstruction of the lateral collateral ligament complex is important in order to prevent residual instability (Fig. 4.6). In acute traumatic injuries, the lateral collateral ligament complex is usually avulsed from the lateral epicondyle. We favor a strong repair with two heavy nonabsorbable sutures grasping the collateral ligament substance as well as the adjacent capsule and common extensors using a Krackow locking stitch configuration. The ends of the suture are passed through bone tunnels at the isometric point on the center of the lateral epicondyle and tied over the bony bridge of the lateral column. In chronic cases, consideration should be given to reconstruction of the lateral collateral ligament complex with a tendon graft.33

POSTOPERATIVE MANAGEMENT

17

The need for postoperative protection is dictated by the associated pathology. For isolated radial head replacement in the absence of other pathology, the arm may be placed on a sling or posterior plaster splint for comfort during the first 2 weeks, P.44

but active motion may be allowed almost immediately if tolerated. Physical therapy is directed to restoration of range of motion with active and active-assisted exercises. There is limited information to guide the degree of lifelong restrictions after radial head replacement. We recommend limited weight lifting but allow most activities of daily living.

FIGURE 4.6 Careful repair of the lateral collateral ligament complex and adjacent capsule and musculotendinous units through bone tunnels.

RESULTS The overall results of radial head replacement are difficult to interpret. This is due in part to considerable variation in the indications, design, follow-up, and outcome tools considered in each particular study. The results reported in several modern peer-reviewed studies are summarized in Table 4.4. In acute complex elbow trauma, replacement

18

of the irreconstructible radial head seems to provide reasonable results in terms of stability, motion, and function, with good or excellent overall results in an average of 84% of the patients. On the contrary, the results seem to be less predictable for reconstruction of chronic conditions, where the rate of satisfactory results seems to be under 50%. There is very limited information about the failure modes of radial head replacement. We recently reviewed the Mayo Clinic experience in a series of 47 elbows that were reoperated to remove or revise a failed radial head implant. The index radial head implant had been placed within 1 week of a radial head fracture in 13 patients and an average of 2.5 years after the initial injury in 23 patients. The most common failure mode was painful loosening of the prosthesis (30 cases; Fig. 4.7). Additional failure mechanisms included stiffness (18 elbows), instability (9 elbows), and deep infection (2 elbows). Only three radiographically loose implants had been fixed with cement, whereas the remaining loose implants were uncemented. Radiographic evidence of instability was found in ten elbows: there was radial head subluxation in four elbows, a complete elbow dislocation in three elbows, and dissociation of the radial head from the stem in three elbows (Fig. 4.8). Ten elbows presented radiographic signs of overlengthening and joint overstuffing (Fig. 4.9). Degenerative changes were found in all prerevision radiographs.

TABLE 4.4 RESULTS OF RADIAL HEAD REPLACEMENT

19

Total no. (Satisfactory)

Foll owup (y)

Author

Ye ar

Imp lant

Ac ute

Dela yed

To tal

Knight et al.22

19 93

Fixe d

31 (94 %)

—

31 (94 %)

4.5

Judet et al.17

19 96

Bipo lar

7 (10 0%)

7 (72 %)

14 (86 %)

4

Wick et al.45

19 98

Fixe d

—

—

3 (73 %)

—

Popovic et al.27

20 00

Bipo lar

11 (83 %)

—

11 (83 %)

2.5

Smets et al.35

20 00

Bipo lar

13 (77 %)

2 (0% )

15 (67 %)

2

Harringt on et al.11

20 01

Fixe d

—

—

20 (80 %)

12

Moro et al.24

20 01

Fixe d

24 (67 %)

—

24 (67 %)

3.2

20

Holmens chlager et al.15

20 02

Bipo lar

10 (10 0%)

6 (67 %)

16 (87 %)

1.5

Alnot et al.1

20 03

Bipo lar

18 (10 0%)

4 (0% )

22 (82 %)

1.5

Ashwoo d et al.2

20 04

Fixe d

10 (10 0%)

4 (0% )

14 (71 %)

2.8

Chapma n et al.4

20 06

Fixe d

8 (10 0%)

8 (87 %)

16 (94 %)

2.7

Dotzis et al.7

20 06

Bipo lar

12 (83 %)

—

12 (83 %)

5.3

Grewal et al.9

20 06

Fixe d

26 (67 %)

—

26 (67 %)

2

Wretenb erg et al.46

20 06

Fixe d

18 (72 %)

—

18 (72 %)

3.7

Doornbe rg et al.6

20 07

Fixe d

27 (82 %)

—

27 (82 %)

3.5

Popovic et al.28

20 07

Bipo lar

51 (76 %)

—

51 (76 %)

8.4

21

Lim and Chan23

20 08

Fixe d

6 (67 %)

—

6 (67 %)

1.8

Shore et al.34

20 08

Fixe d

—

32 (66 %)

32 (66 %)

8

272 (84 %)

63 (41 %)

35 8 (78 %)

4

Total

FIGURE 4.7 Radiographic loosening is reported to be well tolerated by some patients, but may generate pain requiring reoperation.

RADIOCAPITELLAR HEMIARTHROPLASTY The combined implantation of a radial head implant and a capitellar implant represents an attractive concept for the treatment of patients

22

with elbow pathology limited to the radiocapitellar joint. This may include acute trauma where the articular P.45

surface of the capitellum was damaged at the time of the radial head fracture but may be more commonly indicated in chronic conditions where a radial head replacement is necessary but the capitellum presents substantial articular and/or bony deficiency (Fig. 4.10). There is very limited experience and published information about radiocapitellar hemiarthroplasty, but it may continue to expand the indications of radial head replacement.12

FIGURE 4.8 Other complications may include instability (A) or dissociation (B).

23

FIGURE 4.9 Excessively large prosthesis may be implanted in an attempt to achieve stability, leading to radial overlengthening and joint overstuffing.

24

FIGURE 4.10 Radiocapitellar hemiarthroplasty. P.46

SUMMARY The radial head plays an important role in the stability and function of the elbow and the forearm. Radial head replacement is commonly considered for the treatment of displaced irreconstructible fractures as well as some chronic conditions. Modern modular metallic implants represent an improvement over old silicone implants. However, controversy persists about the ideal fixation mode as well as the relative indications of fixed and bipolar prosthesis. A successful radial head replacement requires accurate restoration of the diameter, length, and tracking of the native radial head. These goals may be much more difficult to achieve in chronic conditions. The results of radial head replacement are difficult to interpret because of the heterogeneous nature of the studies published to date. The main reasons for implant

25

failure requiring reoperation include painful loosening, stiffness, instability, and deep infection.

References 1. Alnot JY, Katz V, Hardy P: GUEPAR radial head prosthesis for recent and old fractures: A series of 22 cases. Rev Chir Orthop Reparatrice Appar Mot 89(4):304-309, 2003. 2. Ashwood N, Bain GI, Unni R: Management of Mason type-III radial head fractures with a titanium prosthesis, ligament repair, and early mobilization. J Bone Joint Surg Am 86-A(2):274-280, 2004. 3. Beredjiklian PK, Nalbantoglu U, Potter HG, Hotchkiss RN: Prosthetic radial head components and proximal radial morphology: A mismatch. J Shoulder Elbow Surg 8(5):471-475, 1999. 4. Chapman CB, Su BW, Sinicropi SM, et al: Vitallium radial head prosthesis for acute and chronic elbow fractures and fracturedislocations involving the radial head. J Shoulder Elbow Surg 15(4):463-473, 2006. 5. Dodds SD, Yeh PC, Slade JF III: Essex-lopresti injuries. Hand Clin 24(1):125-137, 2008. 6. Doornberg JN, Parisien R, van Duijn PJ, Ring D: Radial head arthroplasty with a modular metal spacer to treat acute traumatic elbow instability. J Bone Joint Surg Am 89(5):1075-1080, 2007. 7. Dotzis A, Cochu G, Mabit C, et al: Comminuted fractures of the radial head treated by the Judet floating radial head prosthesis. J Bone Joint Surg Br 88(6):760-764, 2006. 8. Fuerst M, Fink B, Ruther W: Survival analysis and longterm results of elbow synovectomy in rheumatoid arthritis. J Rheumatol 33(5):892896, 2006. 9. Grewal R, MacDermid JC, Faber KJ, et al: Comminuted radial head fractures treated with a modular metallic radial head arthroplasty. Study of outcomes. J Bone Joint Surg Am 88(10):2192-2200, 2006. 10. Gupta GG, Lucas G, Hahn DL: Biomechanical and computer analysis of radial head prostheses. J Shoulder Elbow Surg 6(1):37-48, 1997. 11. Harrington IJ, Sekyi-Otu A, Barrington TW, et al: The functional outcome with metallic radial head implants in the treatment of unstable elbow fractures: A long-term review. J Trauma 50(1):46-52, 2001.

26

12. Heijink A, Morrey BF, Cooney WP III: Radiocapitellar hemiarthroplasty for radiocapitellar arthritis: A report of three cases. J Shoulder Elbow Surg 17(2):e12-e15, 2008. 13. Herbertsson P, Josefsson PO, Hasserius R, et al: Fractures of the radial head and neck treated with radial head excision. J Bone Joint Surg Am 86-A(9):1925-1930, 2004. 14. Herbertsson P, Josefsson PO, Hasserius R, et al: Uncomplicated Mason type-II and III fractures of the radial head and neck in adults. A long-term follow-up study. J Bone Joint Surg Am 86-A(3):569-574, 2004. 15. Holmenschlager F, Halm JP, Winckler S: Fresh fractures of the radial head: Results with the Judet prosthesis. Rev Chir Orthop Reparatrice Appar Mot 88(4):387-397, 2002. 16. Johnson JA, Beingessner DM, Gordon KD, et al: Kinematics and stability of the fractured and implant-reconstructed radial head. J Shoulder Elbow Surg 14(1 Suppl S):195S-201S, 2005. 17. Judet T, Garreau de Loubresse C, Piriou P, Charnley G: A floating prosthesis for radial-head fractures. J Bone Joint Surg Br 78(2):244249, 1996. 18. Kamineni S, Maritz NG, Morrey BF: Proximal radial resection for posttraumatic radioulnar synostosis: A new technique to improve forearm rotation. J Bone Joint Surg Am 84-A(5):745-751, 2002. 19. Kaplan EB: Surgical approach to the proximal end of the radius and its use in fractures of the head and neck of the radius. J Bone Joint Surg 23(1):86-92, 1941. 20. King GJ, Zarzour ZD, Patterson SD, Johnson JA: An anthropometric study of the radial head: implications in the design of a prosthesis. J Arthroplasty 16(1):112-116, 2001. 21. King GJ, Zarzour ZD, Rath DA, et al: Metallic radial head arthroplasty improves valgus stability of the elbow. Clin Orthop Relat Res (368):114-125, 1999. 22. Knight DJ, Rymaszewski LA, Amis AA, Miller JH: Primary replacement of the fractured radial head with a metal prosthesis. J Bone Joint Surg Br 75(4):572-576, 1993. 23. Lim YJ, Chan BK: Short-term to medium-term outcomes of cemented vitallium radial head prostheses after early excision for radial head fractures. J Shoulder Elbow Surg 17(2):307-312, 2008.

27

24. Moro JK, Werier J, MacDermid JC, et al: Arthroplasty with a metal radial head for unreconstructible fractures of the radial head. J Bone Joint Surg Am 83-A(8):1201-1211, 2001. 25. Morrey BF, Schneeberger AG: Anconeus arthroplasty: A new technique for reconstruction of the radiocapitellar and/or proximal radioulnar joint. J Bone Joint Surg Am 84-A(11):1960-1969, 2002. 26. Pomianowski S, Morrey BF, Neale PG, et al: Contribution of monoblock and bipolar radial head prostheses to valgus stability of the elbow. J Bone Joint Surg Am 83-A(12):1829-1834, 2001. 27. Popovic N, Gillet P, Rodriguez A, Lemaire R: Fracture of the radial head with associated elbow dislocation: results of treatment using a floating radial head prosthesis. J Orthop Trauma 14(3):171-177, 2000. 28. Popovic N, Lemaire R, Georis P, Gillet P: Midterm results with a bipolar radial head prosthesis: Radiographic evidence of loosening at the bonecement interface. J Bone Joint Surg Am 89(11):2469-2476, 2007. 29. Pugh DM, Wild LM, Schemitsch EH, et al: Standard surgical protocol to treat elbow dislocations with radial head and coronoid fractures. J Bone Joint Surg Am 86-A(6):1122-1130, 2004. 30. Ring D, Jupiter JB, Zilberfarb J: Posterior dislocation of the elbow with fractures of the radial head and coronoid. J Bone Joint Surg Am 84-A(4): 547-551, 2002. 31. Ring D, Quintero J, Jupiter JB: Open reduction and internal fixation of fractures of the radial head. J Bone Joint Surg Am 84-A(10):18111815, 2002. 32. Rowland AS, Athwal GS, MacDermid JC, King GJ: Lateral ulnohumeral joint space widening is not diagnostic of radial head arthroplasty overstuffing. J Hand Surg [Am] 32(5):637-641, 2007. 33. Sanchez-Sotelo J, Morrey BF, O'Driscoll SW: Ligamentous repair and reconstruction for posterolateral rotatory instability of the elbow. J Bone Joint Surg Br 87(1):54-61, 2005. 34. Shore BJ, Mozzon JB, MacDermid JC, et al: Chronic posttraumatic elbow disorders treated with metallic radial head arthroplasty. J Bone Joint Surg Am 90(2):271-280, 2008. 35. Smets S, Govaers K, Jansen N, et al: The floating radial head prosthesis for comminuted radial head fractures: A multicentric study. Acta Orthop Belg 66(4):353-358, 2000.

28

36. Smith AM, Urbanosky LR, Castle JA, et al: Radius pull test: Predictor of longitudinal forearm instability. J Bone Joint Surg Am 84A(11):1970-1976, 2002. 37. Speed K: Ferrule caps for the head of the radius. Surg Gynecol Obstet 73:845, 1941. 38. Stanley JK, Penn DS, Wasseem M: Exposure of the head of the radius using the Wrightington approach. J Bone Joint Surg Br 88(9):1178-1182, 2006. 39. Swanson AB, Jaeger SH, La Rochelle D: Comminuted fractures of the radial head. The role of silicone-implant replacement arthroplasty. J Bone Joint Surg Am 63(7):1039-1049, 1981. 40. Swieszkowski W, Skalski K, Pomianowski S, Kedzior K: The anatomic features of the radial head and their implication for prosthesis design. Clin Biomech (Bristol, Avon) 16(10):880-887, 2001. 41. Van Glabbeek F, Van Riet RP, Baumfeld JA, et al: Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow. J Bone Joint Surg Am 86-A(12):2629-2635, 2004. 42. Van Riet RP, Van Glabbeek F, Neale PG, et al: The noncircular shape of the radial head. J Hand Surg [Am] 28(6):972-978, 2003. 43. Van Riet RP, Van Glabbeek F, Verborgt O, Gielen J: Capitellar erosion caused by a metal radial head prosthesis. A case report. J Bone Joint Surg Am 86-A(5):1061-1064, 2004. 44. Vanderwilde RS, Morrey BF, Melberg MW, Vinh TN: Inflammatory arthritis after failure of silicone rubber replacement of the radial head. J Bone Joint Surg Br 76(1):78-81, 1994. 45. Wick M, Lies A, Muller EJ, et al: Prostheses of the head of the radius. What outcome can be expected?. Unfallchirurg 101(11):817821, 1998. 46. Wretenberg P, Ericson A, Stark A: Radial head prosthesis after fracture of radial head with associated elbow instability. Arch Orthop Trauma Surg 126(3):145-149, 2006. 47. Yian E, Steens W, Lingenfelter E, Schneeberger AG: Malpositioning of radial head prostheses: an in vitro study. J Shoulder Elbow Surg 17(4):663-670, 2008.

29

Chapter 5 Capitellar Prosthetic Replacement Bernard F. Morrey

INTRODUCTION In this chapter, we describe the concept and the rationale for capitellar replacement; however, lack of outcome data should be noted at this point in time. Hence, our goal is principally to call attention to the pathology and to highlight emerging options and thought process for its management.

ETIOLOGY Like so many other pathologic conditions, it seems as though the condition is more frequent once we are attuned to investigate for its presence. The most common etiology is probably primarily osteoarthritis at the elbow, generally considered uncommon in the past, but today it is a well-recognized diagnosis in the orthopaedic community.3 , 6 , 10 , 11 In other instances, the pathology of the capitellum is from capitellar trauma, follows radial head fracture, or is a sequela of osteochondritis dissecans (Fig. 5.1). The frequency of these various conditions is not readily available in today's literature. Although there have been some investigations of the involvement of the radiohumeral joint in primary osteoarthritis of the elbow, the frequency of the problem is not well-defined. Of the several expressions of capitellar involvement in primary osteoarthritis, only eburnation of the capitellum is generally considered a candidate for intervention. Narrowing of the ulnohumeral joint is not a typical characteristic of primary osteoarthritis but may be seen at the radiohumeral joint. Goodfellow et al. documented the increasing incidence of osteoarthritis of the radiohumeral joint with aging and emphasized the early development of the process at the posterior medial ridge that separates the trochlea and the capitellum (Fig. 5.2). In general, heavy, repetitive use of the extremity places the joint at risk.4 , 11 With increased awareness, the presence of significant radiohumeral joint symptoms is being increasingly appreciated. Hence, Kelly et al.7 specifically documented radiohumeral narrowing during debridement for

1

osteoarthritis of the elbow. They noted that the radial humeral involvement appears to be well tolerated and typically need not be directly addressed at the time of surgery. Radiographically, radial head involvement has been documented in approximately 85%, but usually is not symptomatic.2 Others have described radial head resection through the arthroscopy during debridement for osteoarthritis and in so doing documented improved motion in both flexion and extension and pronation and supination.9 The long-term impact, however, of removing the radial head in the presence of ulnohumeral joint arthrosis is unknown. This is one of the major issues that prompt one to consider the possibility of replacing this joint if it is sufficiently symptomatic. Finally, fracture of the capitellum is not common but commonly leads to severe capitellar arthrosis (Fig. 5.3).

TREATMENT OPTIONS Experience to date on the treatment of isolated radiohumeral arthrosis or particularly a capitellar arthritis is quite limited. In general, the treatment options include debridement, resection, or reconstruction.1 , 8 , 12 , 13 There is very little data of the outcome of resecting or debriding the capitellum. Hence, interposition arthroplasty or prosthetic replacement of the capitellum and/or the capitellum and radial head is worthy of consideration. One of the greatest problems at the radiohumeral joint is related to problems at the articulation after the radial head has been fractured. Unsuccessful treatment by fixation or prosthetic replacement causes secondary capitellar arthrosis. Under these circumstances, the arthritic radial head is excised or the malaligned prosthesis is removed. If the medial collateral ligament is stable, this is often adequate treatment. If, however, the medial collateral ligament is deficient, replacement of the radiohumeral joint is a reasonable consideration.

CAPITELLAR PROSTHETIC REPLACEMENT Indications Specific indications are a painful radiohumeral joint when simple excision of the radial head is not viable due to the need to stabilize the lateral joint. This is present when (a) there is a need to stabilize the lateral column due to deficiency of the medial collateral ligament or (b)

2

in those in whom there is axial radial instability in the face of capitellar arthrosis or deficiency. Further, the capitellum may be replaced to articulate with the native radial head (Fig. 5.3) or in conjunction with a radial head replacement (Fig. 5.4). The latter requires a polyethylene articulation to articulate with the metallic capitellar device (Fig. 5.5).

Surgical Technique Herein we describe the surgical insertion of the “uni joint” (Small Bone Innovations, Inc., Morrisville, Pennsylvania). P.48

3

FIGURE 5.1 Radiohumeral arthritis with primary involvement of the capitellum after capitellar fracture (A). The distal T-condylar fracture has malunited resulting in isolated radiohumeral arthritis (B). Osteochondritis dissecans can progress to symptomatic radiohumeral arthritis (C). P.49

4

FIGURE 5.2 Radiohumeral involvement from primary osteoarthritis is seen on the plane film (A). The CT image is more effective to demonstrate the extent of the process (B).

5

FIGURE 5.3 This patient has traumatic arthritis of the capitellum (A, B). Although the radial head is involved, it is maintained since it is felt to be a more reliable articulation than a prosthetic radial head (C, D). P.50

FIGURE 5.3 (Continued).

6

FIGURE 5.4 Radiograph showing medial collateral ligament laxity and lateral column instability due to significant resection of the radial head and neck (A). Patient treated with capitellar implant and an augmented neck radial head prosthetic replacement (B). Note that a normal ulnohumeral relationship has been restored (B). P.51

7

FIGURE 5.5 The radiocapitellar replacement includes a metallic articulation of the capitellum and a polyethylene articulation of the radial head. (With permission from Small Bone Innovations, Inc.) Step 1: Incision—The patient is placed supine and under a general or a regional anesthesia. We prefer to bring the arm across the chest. A classic 6 to 8 cm Kocher skin incision is made identifying the interval between the anconeus and the extensor carpi ulnaris and is carried down to the joint capsule. Alternatively, a Kaplan incision through the extensor mechanism and supinator muscle may be made. Step 2: Exposure—The capsule is exposed by elevating a portion of the extensor carpi ulnaris sufficiently to allow identification of the lateral collateral ligament complex (Fig. 5.6). Alternatively, the extensor carpi ulnaris may be split longitudinally with its fibers staying anterior to the humeral attachment and isolating the lateral collateral ligament. The lateral collateral ligament can be reflected off the lateral epicondyle to expose the capitellum. If the ligament has been disrupted, then the exposure progresses through the site of disruption to expose the radiohumeral joint. The common extensor tendon and elbow joint capsule are retracted as needed to maximize exposure.

8

FIGURE 5.6 The radial head is exposed in a typical fashion. We employ the Kocher interval. The capsule is entered and the attachment to the humerus is released sufficiently to provide adequate exposure for the intended surgery. (With permission from Small Bone Innovations, Inc.)

9

FIGURE 5.7 After the flexion axis has been identified (A), the resection is of a chevron type. A distal guide is employed initially to avoid excessive resection (B). (With permission from Small Bone Innovations, Inc.) If the radial head is intact, a more extensive soft tissue release is necessary. Step 3. Axis of flexion rotation—A drill guide based on the medial epicondyle allows a drill to be inserted that replicates the axis of rotation. Leaving the axis reference K-wire in place, remove the axis of rotation locator clamp and template. Step 4: Capitellar resection— Based on the size of the capitellum, place the large or small resection guide and align the handle so that it is parallel with the long axis of the humerus (Fig. 5.7). Remove the appropriate amount of capitellum surface but do not involve the trochlea. Step 5: Capitellum trial and stem reference—Place the capitellum trial firmly against the resected surfaces (Fig. 5.8). Insert the reference K-wire that serves as the alignment pin for subsequent preparation and stem insertion. Step 6: Broaching of the distal humerus—Remove the trial capitellum and pass the cannulated 0.35-mm drill over the center Kwire into the distal humerus to create the broach pilot hole. Align the arm of the broach with the apex of the chevron cut and into the pilot hole. Advance until the teeth are flush with the capitellum cut surface (Fig. 5.9). Step 7: Implanting the final component—Distraction of the proximal radius as well as flexion of the elbow may be necessary to allow sufficient access for capitellum insertion. Note: The radio-capitellar implant is intended for cemented use only. Use without cement or of the capitellar replacement P.52

alone, without the radial head are not yet approved by FDA, and hence is considered an off label application.

10

FIGURE 5.8 A trial reduction allows the insertion of a reference pin that is used to direct a cannulated drill followed by a cannulated rasp. (With permission from Small Bone Innovations, Inc.) Step 8: Closure—A No. 5 nonabsorbable suture is placed at the humeral origin of the lateral collateral ligament and a running locked stitch proceeds distally through the ulnar attachment, then back proximally, exiting at the humeral origin of the ligament (Fig. 5.10).

11

FIGURE 5.9 The cannulated rasp is carefully aligned to match the apex of the chevron cut. This provides proper orientation for insertion of the capitellar replacement. (With permission from Small Bone Innovations, Inc.)

Aftercare The motion that is allowed is primarily based on the status of lateral collateral repair. Usually, both flexion/extension and pronation/supination arcs are allowed without restriction and active motion can begin by day 7.

12

FIGURE 5.10 It is important to stabilize the joint following insertion. We typically employ a running locked stitch using a heavy No. 5 nonabsorbable suture. (Copyright, Mayo Foundation)

Clinical Results There is limited data regarding the utility of capitellar prosthetic replacements. We have observed effective treatment of chronic EssexLopresti lesions in three patients.5 In our initial 12 patients treated for various indications, we have not as yet revised any to date. The largest experience to date constituting 44 capitellar prostheses of a different design (Biomet, Warsaw ID) has been assembled by Pooley (Personal communication: Pooley J: The development, indications and early results of a lateral resurfacing elbow (LRE) arthroplasty, Queen Elizabeth Hospital, Gateshead, UK). Exactly half, 22, also had a resurfacing replacement of the radial head. No outcomes are available. Time will tell.

References 13

1. Antuna SA, Morrey BF, Adams RA, O'Driscoll SW: Ulnohumeral arthroplasty for primary degenerative arthritis of the elbow: Long-term outcome and complications. J Bone Joint Surg 84A(12):2168-2173, 2002. 2. Dalal S, Bull M, Stanley D: Radiographic changes at the elbow in primary osteoarthritis: A comparison with normal aging of the elbow joint. J Shoulder Elbow Surg 16(3):358-361, 2007. 3. Doherty M, Watt I, Dieppe PA: Influence of primary generalized osteoarthritis on development of secondary osteoarthritis. Lancet 2:8, 1983. 4. Goodfellow JW, Bullough PG: The pattern of aging of the articular cartilage of the elbow joint. J Bone Joint Surg 49B(1):175-181, 1967. 5. Heijink A, Morrey BF, van Riet RP, et al: Delayed treatment of elbow pain and dysfunction following Essex-Lopresti injury with metallic radial head replacement. Submitted for publication, J Bone Joint Surgery [Am] 2010. 6. Kashiwagi D: Intra-articular changes of the osteoarthritic elbow, especially about the fossa olecrani. Jpn Orthop Assoc 52:1367, 1978. 7. Kelly EW, Bryce R, Coghlan J, Bell S: Arthroscopic debridement without radial head excision of the osteoarthritic elbow. Arthroscopy 23(2): 151-157, 2007. 8. Krishnan SG, Harkins DC, Pennington SD, et al: Arthroscopic ulnohumeral arthroplasty for degenerative arthritis of the elbow in patients under fifty years of age. J Shoulder Elbow Surg 16(4):443-448, 2007. 9. McLaughlin RE II, Savoie FH III, Field LD, Ramsey JR: Arthroscopic treatment of the arthritic elbow due to primary radiocapitellar arthritis. Arthroscopy 22(1):63-69, 2006. 10. Minami M, Ishii S: Outerbridge-Kashiwagi Arthroplasty for Osteoarthritis of the Elbow Joint. New York, Elsevier Science, 1985, pp 189-196. 11. Mintz G, Fraga A: Severe osteoarthritis of the elbow in foundry workers. Arch Environ Health 27:78, 1973. 12. Morrey BF, Schneeberger AG: Anconeus arthroplasty: A new technique for reconstruction of the radiocapitellar and/or proximal radioulnar joint. J Bone Joint Surg 84A(11):1960-1969, 2002.

14

13. Ortner DJ: Description and classification of degenerative bone changes in the distal joint surface of the humerus. Am J Phys Anthropol 28:139, 1968.

15

Chapter 6 Hemiarthroplasty of the Elbow Scott P. Steinmann

HISTORICAL PERSPECTIVE Hemiarthroplasty for elbow reconstruction has been mentioned only briefly in the orthopaedic literature since the 1940s. All reports involve a description of the replacement of the distal portion of the humerus. Partial replacement of only the ulnar side of the joint has not been described. Mellen and Phalen6 first reported in 1947 the use of an acrylic prosthesis, which was designed to articulate with the greater sigmoid notch of the ulna. It had an interesting design in that the proximal part of the prosthesis was a tube and the humerus was placed down into the prosthesis and secured with wire sutures. The results were reasonably encouraging, and the prosthesis provided patients with acceptable range of motion and excellent pain relief. Significant follow-up, however, was lacking with a less than 2-year follow-up in their series. In 1954, McAusland5 reported on a series of four patients treated with a new type of hemiarthroplasty. This was a nylon prosthesis, which was shaped to duplicate the distal portion of the humerus. Importantly, it provided complete replacement for the epicondyles and the articular surface. It was also designed to be driven up into the humeral shaft for a pressfit without additional cement, suture, or screw fixation. The longest follow-up in his series was 3 years, and most of the patients underwent replacement for the sequelae of untreated elbow trauma, including malunion or nonunion. Of note, in his series although followup was relatively short, all patients achieved excellent pain relief with no instability noted at the prosthetic ulnar articulation. McAusland summed up the report's careful enthusiasm, “the time has not yet come to recognize immediate prosthetic reconstruction in every recent, severe, intracondylar fracture. Its use is recommended only in the cases in which there is no question as to the poor prognosis under treatment by [fracture] reduction.” In 1965, Barr and Eaton3 presented a case report of a 30-year-old auto mechanic who had a previous nonunion of the distal humerus fracture with malalignment of the articular surfaces. They performed a resection

1

of the comminuted distal humeral nonunion and replaced this with a custom-made vitallium prosthesis (Fig. 6.1). Importantly, this prosthesis resulted in complete resection of the epicondyles but provided suture holes through the metal replacement epicondyles for attempted reattachment of the medial and lateral musculature. The prosthesis itself was a press-fit design that was modeled after an early hip nail and was seated with a mallet. Screw fixation from a posterior direction was placed through both the shaft of the humerus and the prosthesis similar to locking screws in a femoral nail. The patient was followed for 4 years and impressively had returned to a very active manual labor career putting severe stress on the prosthesis. At 4-year follow-up, one of the screws had broken but he had switched to a less strenuous job and his elbow was symptom free. A similar type of prosthesis was implanted in 1965 in a case report by Shifrin and Johnson8 who presented a 20-year follow-up of an elbow hemiarthroplasty. In that year, they treated a 19-year-old man who had a comminuted distal humerus fracture treated by open reduction internal fixation with subsequent infection requiring two surgeries in an attempt to control the infection. Later that year after the infection had been treated, the nonunion of the distal humerus fracture was resected and a custom vitallium endoprosthesis was implanted (Fig. 6.2A,B). Similar to the custom design that Barr and Eaton utilized, this prosthesis was implanted without cement in a press-fit manner and was an entire replacement of the distal humerus. Suture holes were placed in the metallic epicondyle for the reattachment of medial and lateral P.54

musculature. Additionally, three bicortical bolts were placed from a posterior direction through the implant similar to the Barr and Eaton prosthesis for secure fixation. At final follow-up at 20 years, the patient stated that “my right elbow is fine and is the same as when it was installed. There is still 140 degrees of motion. I work out at the YMCA on universal weights. It is not as strong as my left elbow but is doing fine.”

2

FIGURE 6.1 Roentgenograms made 4 years after arthroplasty. Slight resorption and new-bone formation have created a cuff of bone around the base of the prosthesis. A thin parallel line of sclerosis is present along the stem suggesting that no significant motion has occurred between the stem and prosthesis. Although the distal screw has broken, no untoward effect in the remaining screw or prosthesis seems to have developed. (From Barr JS, Eaton RG: Elbow reconstruction with a new prosthesis to replace the distal end of the humerus: A case report. J Bone Joint Surg 47A(7):1411, 1965, Fig. 6, with permission). Following these encouraging series of case reports, the largest series in the literature on the subject of hemiarthroplasty of the elbow was published by Street and Stevens in 1974.9 They reported on ten patients who had undergone endoprosthetic replacement of the distal part of the humerus including five posttraumatic lesions: three with

3

rheumatoid arthritis and two with ankylosis secondary to hemophilia. The prosthesis was made of stainless steel or titanium and was essentially a cap resurfacing of the distal humerus (Fig. 6.3). This Ushaped prosthesis was placed into the elbow from a medial approach with takedown of the medial collateral ligament while preserving the lateral collateral ligament. The distal articular surface was removed with the use of handheld burr, and the prosthesis itself was driven with a mallet across the distal articular surface of the humerus in a press-fit manner. No cement, pins, or screws were used to maintain its position. Due to its resurfacing nature, the attachment site of the medial collateral ligament was preserved and this was reconstructed at the end of the procedure. In their report, they presented a 7-year follow-up in one patient who was an electrician who had returned to full work activity and reported no pain or disability (Fig. 6.4). The result in patients with rheumatoid arthritis was less satisfactory with somewhat less postoperative range of motion. Importantly, in none of the ten cases was loosening of the prosthesis a complication and instability of the elbow joint did not occur. They concluded that hemiarthroplasty of the elbow seems to offer satisfactory pain relief. The authors felt that use of cement fixation is probably not necessary in elbow arthroplasty.

4

FIGURE 6.2 A: Anteroposterior and (B) lateral roentgenograms of the right elbow 6 weeks postoperative. The patient was able to actively flex to approximately 90 degrees. (From Shifrin PG, Johnson DP: Elbow hemiarthroplasty with 20-year followup study: A case report and literature review. Clin Orthop Relat Res 254:130, 1990, Fig. 1A, B, with permission).

5

FIGURE 6.3 The prosthesis. (From Street DM, Stevens PS: A humeral replacement prosthesis for the elbow: Results in 10 elbows. J Bone Joint Surg 56A(6):1148, 1974, Fig. 1, with permission). After Street and Stevens' cautiously enthusiastic report on the results of hemiarthroplasty for the elbow, very little was written on the subject through the 1980s and early 1990s. It would seem that enthusiasm for the procedure, at least in the orthopaedic literature, had waned. At this same time period, many of the modern elbow arthroplasty designs had been developed and many reports had been published describing the techniques and results of total elbow arthroplasty. Although elbow hemiarthroplasty was not reported on and newer designs were not developed during this time period, if one looks back at these earlier case reports from the 1950s to 1960s, a common thread is the apparent viability of hemiarthroplasty in the posttraumatic situation. Most of the patients in these case reports had returned to full activity as tolerated and were not given restrictions. It is impressive that most of these prostheses, particularly those that allowed for complete replacement of the distal humerus, did not have complications related to loosening of the prosthesis or dislocation of the ulnohumeral joint. It is important to note, however, that other than a few instances most of the follow-up was less than 2 to 3 years, the single case report of a 20year follow-up being the exception.

6

It was not until 1999 that the next report in the literature on the use of hemiarthroplasty for the elbow appeared.10 Swoboda and Scott reported on the use of the Ewald capitellocondylar prosthesis. This system was designed as a complete total elbow arthroplasty, but in the seven patients in this series, only P.55

the humeral component was implanted. The patients were chosen for hemiarthroplasty due to their young age, averaging 33 years, mainly in female rheumatoid patients, several of whom had juvenile rheumatoid arthritis.

FIGURE 6.4 A, B: Four years after arthroplasty. (From Street DM, Stevens PS: A humeral replacement prosthesis for the elbow: Results in 10 elbows. J Bone Joint Surg 56A(6):1153, 1974, Fig. 7B, with permission). The authors reported that the most impressive changes postoperatively were pain relief with four of the seven patients being pain free and all the patients being very satisfied. What was distinctly different from the larger series of capitellocondylar total elbow arthroplasty was a disappointing range of motion reported by the authors. As compared to Ewald's report on total elbow arthroplasty where the average range of motion was from 37 to 118 degrees, in this small group of seven patients, the postoperative range of motion was only 60 to 98 degrees.

7

Importantly, the postoperative radiographs in this small series did not show any sign of loosening of the cemented component. In one of the patients who was followed for 6 years, the lateral radiograph showed the humeral component eroding through the trochlear notch of the ulna. The authors questioned whether this erosion might progress for a long term in patients with rheumatoid arthritis and whether these patients might ultimately require implantation of an ulnar component. The use of an elbow hemiarthroplasty has been advocated by some as a treatment for distal humerus fracture in the elderly patient. Adolfsson and Hammer1 reported from Sweden a small series of four patients, the average age being 80 years, all female, who had suffered a distal humeral intraarticular fracture. In their series, the Kudo humeral component was used. The authors also performed radial head excision in these patients and preserved the origin of the collateral ligaments and repaired any fracture of the medial or lateral columns at the time of component implantation with cement. It is important to note that the Kudo humeral component is a nonanatomic replacement of the distal humerus. Nonetheless, at relatively short follow-up of 10 months, all four patients had significant pain relief and had been using the extremity for daily activities. No instability of the ulnohumeral joint or implant loosening was reported. It is interesting to note that the authors felt that hemiarthroplasty would be more relevant in the elderly patient and did not recommend the technique for the younger patient. This viewpoint is perhaps different than what other surgeons with experience in elbow replacement might express. A total elbow arthroplasty has certainly been shown to be a reliable technique for pain relief and range of motion in the elderly population.4 In 2005, Parsons et al.7 reported short-term data on eight patients undergoing hemiarthroplasty with the Sorbie-Questor prosthesis. Four of their patients were treated for an acute fracture and four for nonacute trauma involving failure of fixation or nonunion. The patients averaged 61 years of age with average postoperative motion from 22 to 126 degrees. All patients had significantly less pain postoperatively, with the patients in the acute trauma group having less pain than the nonacute patients. Although the follow-up was relatively short, importantly no patient in their series developed sepsis, loosening, or

8

instability of the prosthesis. One patient had developed sclerosis of the greater sigmoid notch consistent with ulnohumeral arthrosis and was being considered for potential conversion to total elbow arthroplasty.

FIGURE 6.5 A-C: Radiographs of a 71-year-old woman with a distal humerus fracture treated with an unlinked total elbow arthroplasty (Latitude, Tornier, Stafford, Texas). Condylar fixation was accomplished with sutures and a tension band construct. (From Athwal GS, Goetz TJ, Pollock JW, Faber KJ: Prosthetic replacement for distal humeral fractures. Orthop Clin North Am 38: 207, 2008, Fig. 4, with permission)

INDICATIONS The indications for hemiarthroplasty of the elbow include patients with a “dry” form of rheumatoid arthritis who are still very active. Current modern pharmacological treatment allows some rheumatoid arthritis patients to be quite active with fully functioning hips and knees with only elbow pain and loss of motion. If on presentation these patients have preservation of their humeral and ulnar bone stock with loss of only the cartilaginous joint space, they are potential candidates for resurfacing of the distal humerus. The other group of patients who potentially might benefit from hemiarthroplasty include patients who have a low condylar sheering fracture of the articular surface.2 It should be emphasized that in recent years precontoured plates designed specifically for the elbow

9

have made many distal humeral fractures amenable to reconstruction. In the case of low distal humeral fractures, the medial and lateral columns are often preserved or if fractured reconstruction of the columns can be achieved. This group of patients would potentially benefit from hemiarthroplasty (Fig. 6.5). The third group of patients who might benefit from a hemiarthroplasty would be those who have undergone either failed open reduction internal fixation or have developed a nonunion of a low distal humerus fracture. A relative contraindication for distal humeral replacement might be in the very elderly patient population who have been shown to do relatively well after the more straightforward and easier to perform procedure of total elbow arthroplasty. Most of the prostheses that have been used recently have been originally designed for implantation as a total elbow arthroplasty. Therefore, use of any of the current designs on the market would involve use in an off-label fashion. Therefore, any use of the current designs should be discussed with perspective patients prior to surgery. Currently, most of the total elbow arthroplasty designs that have been used for elbow P.56

hemiarthroplasty have involved significant bone resection of the distal humerus, since most have been designed as a semiconstrained complete replacement. As described previously, there is very little data published on the use of hemiarthroplasty for the elbow, but certainly, the earlier case reports have described reasonable results without significant loosening or instability.11 The best design would require minimal bone resection of the distal humerus and allow for potential revision to a semiconstrained total elbow arthroplasty. The author has used the Sorbie-Questor implant for the replacement of the distal humerus and the surgical technique will now be described (Fig. 6.6).

10

FIGURE 6.6 Distal humeral articular nonunion (A). Distal humeral hemiarthroplasty with the Sorbie implant (B). (From Throckmorton TW, Zarkadas PC, Steinmann SP:

11

Distal humeral fractures. Hand Clin 23(4):266, 2007, Fig. 8, with permission). Successful 1-year outcome (C, D). P.57

SURGICAL TECHNIQUE The patient undergoing hemiarthroplasty of the elbow is placed typically in the supine position with the arm across the chest. The surgeon stands on the fractured side of the patient and has a posterior view of the elbow. The forearm is often placed across a padded bolster, with the operative table tilted slightly away from the surgeon. A posterior midline incision is made and thick flaps are created on both the medial and lateral sides. The ulnar nerve is typically identified and dissected free and transposed anteriorly. In the acute setting, if there is a fracture of the medial or lateral epicondyles, this can be used to the surgeon's advantage and the condyle can be retracted distally with the attached musculature allowing for visualization of the fracture site. Once the ulnar nerve has been transposed, there are three potential approaches to the elbow joint itself. An osteotomy of the olecranon can be performed, and this can be done in a chevron type of osteotomy or a simpler straight transverse cut of the olecranon. This is typically done in thirds: the very dorsal third of the olecranon is cut with a saw, an osteotome is used to cut through the middle portion of the olecranon, and then finally the more anterior portion of the olecranon is fractured off with the use of the osteotome as a lever. This cut should be directed toward the midportion of the greater sigmoid notch at the nonarticular portion of the joint. This should be confirmed by visualizing the joint. An alternative to olecranon osteotomy is either detaching the triceps from the tip of the olecranon as in the Bryan-Morrey approach or performing a transection of the triceps proximal to its insertion on the olecranon. A third technique that the author has used to benefit in the acute trauma situation is to preserve the triceps attachment to the olecranon and expose the fracture site through the fractured condyles— the distal portion of the humerus can then be resected and

12

exposure of the humeral shaft achieved. If the condyles are not fractured, an approach that can be quite helpful is to perform an osteotomy of either the medial or lateral epicondyle, depending on the fracture configuration. Osteotomy of the condyle combined with either an olecranon osteotomy or dislocation of the humerus through the fracture site can often provide good visualization of the distal humerus for implantation. The Sorbie-Questor implant is recommended to be used only if there is good supporting bone of both columns. If one column is completely intact and the other column can be adequately fixed with plate and screws, then the implant can potentially be used. If both columns are fractured and felt to be nonreconstructible, then a semiconstrained total elbow arthroplasty should be performed instead. Typically, after the distal humerus has been exposed in either the acute or the chronic nonunion setting, the fractured portion of the joint is removed and the humerus is prepared for reaming. The Sorbie system contains three different widths of the distal prosthesis but maintains the same length of the humeral stem. This humeral stem is textured and has a slight bend in the component. Because of this, two things must be remembered. If the prosthesis is ever to be revised, the combination of the bend in the prosthesis and the textured surface of the implant means that to remove a well-fixed, cemented implant, the entire length of the stem will need to be exposed by cutting a window in the posterior humerus. This, of course, would be a significant undertaking in the salvage setting. The humeral canal is prepared in the standard fashion using hand reamers and a burr. The cutting guides for the Sorbie total elbow arthroplasty are felt not to be helpful in the hemiarthroplasty setting. The combination of a microsagittal saw and a 3- to 4-mm burr is used to carefully make hand cuts in the distal humerus and a trial implant is then placed over the distal humerus. This is an important part of the procedure and significant time should be spent sizing the bone of the distal humerus to get a tight press-fit of the resurfacing implant. Again, as mentioned previously, this implant depends on a resurfacing pressfit over the distal humerus for stability and is ideally not dependent upon the stem in the humeral shaft for long-term support.

13

After the trial implant has been selected, the ulnohumeral joint is reduced and placed through a range of motion to see if adequate stability has been achieved. This is a very important aspect of the procedure and a posterior drawer is performed to see if the ulna can be unseated from the distal humeral implant. There should be no easy separation or looseness of the ulna and the humeral implants. It should, however, move in a full range of flexion and extension. A cement restrictor is used while placing the final implant to prevent cement extruding up into the proximal shaft of the humerus. Additionally, methylene blue is placed into the cement. Use of methylene blue makes identification of cement versus bone easier if later revision arthroplasty is warranted. It should be emphasized that during repair, the origin of the medial or lateral ligament complex and musculature should be preserved. It is not recommended to detach the lateral collateral ligament or medial collateral ligament from their bony origins on the humerus. Preserving these attachments will greatly influence postoperative stability. If adequate epicondylar reconstruction has been performed, the elbow should have immediate stability. Postoperatively, the arm is placed in a splint in extension and is placed in the Statue of Liberty position and kept fully elevated for 24 hours. The patient is often discharged from the hospital on the first postoperative day. Beginning immediate postoperative motion depends on the quality of the reconstructed epicondyles. It is emphasized that the radial head should not be resected. The radial head is felt to bring significant stability to the joint, and resection of the radial head would compromise the patient's postoperative activity level. If strong fixation of the epicondyles has been achieved at surgery, the patient is allowed to begin use of the arm as tolerated. Formal therapy is generally not instituted but the patient is told to begin full flexion and extension of the arm. In contradistinction to total elbow arthroplasty, where restrictions of lifting only up to 10 pounds at a time or 1 pound repetitively are typically suggested, the patient after successful hemiarthroplasty may return to normal daily activities. He or she is not encouraged to return to a manual labor type occupation, but is not given any restrictions in activities of daily lifting.

14

The author's observation on the outcome of hemiarthroplasty is similar to that which has been reported over the past half century in the literature. Range of motion after a hemiarthroplasty is not as reliable as that achieved after total elbow arthroplasty. Pain relief although significant is also not felt to be as reliable as after a total elbow arthroplasty. In summary, there is little data in the orthopaedic literature to guide the elbow or trauma surgeon in the proper indication and contraindications of hemiarthroplasty. Although little has been written on the subject, a common theme is that pain relief is significant with rare loosening or instability of the joint or of the implant. In the next decade, perhaps based on the cautiously enthusiastic reports of other elbow surgeons, commercial designs specifically for elbow hemiarthroplasty might be developed. P.58

References 1. Adolfsson L, Hammer R: Elbow hemiarthroplasty for acute reconstruction of intraarticular distal humerus fractures. A preliminary report involving 4 patients. Acta Orthop 77(5): 785-787, 2006. 2. Athwal GS, Goetz TJ, Pollock JW, Faber KJ: Prosthetic replacement for distal humerus fractures. Orthop Clin North Am 39(2): 201-212, vi, Review, 2008. 3. Barr JS, Eaton RG: Elbow reconstruction with a new prosthesis to replace the distal end of the humerus. A case report. J Bone Joint Surg 47A(7): 1408-1413, 1965. 4. Kamineni S, Morrey BF: Distal humeral fractures treated with noncustom total elbow replacement. J Bone Joint Surg 86A(5):940-947, 2004. 5. McAusland WR: Replacement of the lower end of the humerus with a prosthesis: A report of four cases. West J Surg Obstet Gynecol 62(11): 557-566, 1954. 6. Mellen RH, Phalen GS: Arthroplasty of the elbow by replacement of the distal portion of the humerus with an acrylic prosthesis. J Bone Joint Surg 29:348-253, 1947.

15

7. Parsons M, O'Brien RJ, Hughes JS: Elbow hemiarthroplasty for acute and salvage reconstruction of intra-articular distal humerus fractures. Tech Shoulder Elbow Surg 6(2): 87-97, 2005. 8. Shifrin PG, Johnson DP: Elbow hemiarthroplasty with 20-year followup study. A case report and literature review. Clin Orthop Relat Res 254: 128-133, 1990. 9. Street DM, Stevens PS: A humeral replacement prosthesis for the elbow: Results in ten elbows. J Bone Joint Surg 56A(6): 1147-1158, 1974. 10. Swoboda B, Scott RD: Humeral hemiarthroplasty of the elbow joint in young patients with rheumatoid arthritis. A report on 7 arthroplasties. J Arthroplasty 14(5): 553-559, 1999. 11. Throckmorton TW, Zarkadas PC, Steinmann SP: Distal humeral fractures. Hand Clin 23(4): 457-469, vi, Review, 2007.

16

Chapter 7 Unlinked Elbow Replacement Arthroplasty Bernard F. Morrey

INTRODUCTION In the third edition of Joint Replacement Arthroplasty, this chapter was entitled “Resurfacing Elbow Replacement Arthroplasty.” We now more properly distinguish two design features when classifying elbow prosthetic designs: linked and unlinked and constrained and unconstrained. These do not correlate to each other as the most constrained implant available today is also unlinked.24 , 61 Since the last edition, issues regarding unlinked implants have also changed globally and at our institution. The reason is that emerging reports have not provided confidence in the design concept in the clinical setting. Further, the main indication of rheumatoid arthritis is being altered by the disease remitting agents.79

The Concept Unlinked elbow replacement was developed largely because the concept of replicating normal anatomy makes intuitive sense and because of the poor early results of more constrained implants. It goes without saying that if one accepts this concept of an anatomic replacement, there must be sufficient bone stock, capsular integrity, and muscle strength to validate the use of an unlinked replacement prosthesis. Most early designs originally lacked stems for a more conservative and possibly easier insertion with more limited exposures14 , 20 , 34 , 51 , 61 , 74 , 77 (Fig. 7.1). However, such implant designs have shown a consistent tendency of fixation failure (Fig. 7.2). Kudo,32 for example, reports 5 of 37 patients with posterior displacement of the nonstemmed humeral implant. Hence, unlinked devices now include both humeral and ulnar intramedullary stems of variable length.

1

FIGURE 7.1 The London implant sought to replicate the articular geometry without the use of stems (A). Failure prompted the addition of stemmed devices (B). A variety of unlinked design strategies to cope with the complex anatomy of the elbow have been tried through the years. Investigators from North America (Figs. 7.3 and 7.4) as well as in Europe and Asia (Fig. 7.5) have designed such devices.8 , 51 , 54 , 58 , 74 The simplest concept is to align the ulnar and humeral shafts using the stems of the components.15 , 17 Normal anatomic relationships are respected and the 5- to 7-degree valgus inclination of the trochlea relative to the anatomic axis of the humerus is generally incorporated in the humeral design.7 , 9 , 33 The normal external rotation of the articulation with respect to the transepicondylar axis is accommodated P.60

by design or technique. The design universally incorporates an angulation of the humeral articulation of approximately 30 degrees to

2

replicate the normal anterior articular orientation.9 , 45 , 50 , 58 Problems have developed with modular polyethylene, so this is not usually a design option today.

FIGURE 7.2 At 5.5 years with an ERS nonstemmed humeral component, the distal humerus fractured and the implant displaced posteriorly. The evolution of the ulnar design has resulted in variable stem designs and lengths. In addition, the trend has increasingly opted for a metallic backing or “tray” to aid implantation and inhibit cold flow deformation of the softer material.10 , 45 The articulation and stem will variably replicate the normal 5- to 7-degree valgus angulation.

3

FIGURE 7.3 Unlinked implants used in the United States. The capitellocondylar implant employed several thicknesses of the high-density polyethylene with varying humeral and ulnar angles to accommodate anatomic variation (A). The ERS implant allows for the replacement of the radial head with a modular system, providing for some flexibility with regard to thickness of the implants (B). The Sorbie device is a three-component device (C). Several recent studies have demonstrated the sensitivity of surgical technique to the specific design type. The Souter-Strathclyde is a highly conforming implant but demonstrates a tendency for internal rotation of the ulna during flexion. This intrinsic tendency was linked to a propensity to insert the humeral component in slight (5-degree) external rotation.56 On the other hand, internal/external rotational malposition of the capitellocondylar implant tends to cause maltracking but does not increase the tendency for instability.21 King et al.23 demonstrated an increased varus/valgus laxity of this device with flexion exceeding 90 degrees. This, coupled with the increased posterior deforming forces at 90 degrees, may account for some of the instability seen with this implant. Further studies have emphasized the need for careful soft tissue balancing.24 The role of the radial head is speculated to enhance force transmission and impart increased stability. In the ERS design, the radial head has been clearly demonstrated to enhance stability in the laboratory.41

4

Unfortunately, in the clinical setting, the medial head has been shown to be a source of failure.73 Clinically, a radial head component was not shown to be of value in the capitellocondylar design.68 Yet, it must be considered when designing an unlinked system.

Indications As with all implants, relentless pain constitutes the best indication for elbow joint replacement. Adequate motion (30-130 degrees) is desirable because stiff joints require extensive dissection, increasing the likelihood of instability.39 Because of the requisite of bone stock and ligament integrity, unlinked replacements are largely reserved for the patient with rheumatoid arthritis. In the radiographic classification system used at the Mayo Clinic, this limits the use to type II or IIIA involvement,40 that is, limited osseous involvement. P.61

In addition to osseous integrity, adequate ligamentous tissue is critical to ensure postoperative stability (Fig. 7.6). As with any prosthetic replacement, absence of infection is a prerequisite. Ideally, the patient should be over 50 years, but, realistically, the technique is used for rheumatoid arthritis at all age. Some consider unlinked devices to be more conservative than linked implants and thus one may prefer this design consider resurfacing more conservative than linked implants and thus one may prefer design for the younger patient.

5

FIGURE 7.4 The Mayo design philosophy initially favored unlinked implants (A) and in some instances quite satisfactory results were obtained (B). The concept was refined (C) but abandoned in 1982 due to instability. The concept of unlinked implants has been revisited by O'Driscoll and colleagues in 2000, as expressed in the latitude design which includes a radial head implant (D).

6

FIGURE 7.5 A: The Souter-Strathclyde device has been widely used in Europe. B: The Kudo design is well-known in the Orient. P.62

7

FIGURE 7.6 This patient has Mayo grade IIIa radiographic involvement with rheumatoid arthritis (A). The capitellocondylar device was a popular one at the Mayo Clinic for over a decade (B). This provided reliable outcomes in a high percentage of patients (C).

Contraindications Active or recent (200 N) will cause plastic deformation as the humeral head dislocates over the rim. However, lower stresses, such as 90 N, cause no such deformation. Furthermore, a combination of shear and compressive forces tends to cause a shearing force that may dissociate the high-density polyethylene from its metal back for support. It is also reasonable to extrapolate these findings to determine the effect on the bone-cement interface. Finally, the concept of fixation as a function of glenoid design has been a cause of major concern with regard to the shoulder joint. Glenoid loosening remains a major concern for the long-term prognosis of the joint. Using a standardized technique, the pullout force of four currently available implants was studied with or without pretest fatigue loading. Fatigue loading did not alter the results of the experiment, P.257

which demonstrated that component fixation strength was greatest in a three-pronged implant and then in the asymmetric keel; finally, the symmetric keeled implant demonstrated the least resistance to axial displacement. This

18

is not a physiologic means of loading this implant, so these data can only be interpreted as experimental.

FIGURE 27.10 Anteroposterior subluxation forces of the humeral component of different glenoid designs using different joint compressive loads.

CONSIDERATIONS OF THE REVERSE SHOULDER PROSTHESIS DESIGN The concept of reversed total shoulder arthroplasty is becoming popular in treating patients with severe rotator cuff tear arthropathy. The basic design concept is that the shift of the center of joint rotation will increase the lever arms of the remaining muscle. In normal anatomy, the center of joint rotation is located at the center of convex surface of the humeral head (Fig. 27.11). In the reversed total shoulder replacement, the convex surface is placed on the glenoid side. Thus, the center of curvature and thus the center of

19

rotation are located in the glenoid component, which is further away from the line of action of the deltoid muscle. Therefore, it is expected to have larger lever arm and be more effective in function of the muscle. Additionally, the concept of reversed total shoulder arthroplasty has advantage in implant fixation. The implant fixation for the glenoid component is usually more critical due to the inferior bony stock. In general, the joint contact forces are directing to the center of curvature (Fig. 27.11). In the normal anatomy or conventional arthroplasty, the joint contact forces on the glenoid surface are in an eccentric manner where the so-called “rocking horse effect” may be encountered and potentially lead to implant loosening. However, in the reversed total shoulder design, the contact force on the glenoid component is more in the concentric manner pointing to the center of curvature where the peg of fixation is located, which is more favorable in reducing the stress at the bony interfaces.

20

FIGURE 27.11 The mechanical considerations of using reversed total shoulder arthroplasty design in treating severe cuff tear arthropathy.

References 1. Bergmann G: Biomechanics and pathomechanics of the shoulder joint with reference to prosthetic joint replacement. In Kölbel R, Helbig B, Blauth W (eds): Shoulder Replacement. Berlin, Springer-Verlag, 1987, p 33. 2. Browne AO, Morrey BF, Hoffmeymer P, et al: Elevation of the arm in the plane of the scapula. J Bone Joint Surg, 72B:843, 1990. 3. Codman EA: The Shoulder. Malabar, Krieger, 1934. 4. Dempster WT: Mechanisms of shoulder movement. Arch Phys Med Rehabil 46A:49, 1965. 5. Doddy SG, Waterland JC, Freedman L: Scapulohumeral goniometer. Arch Phys Med Rehabil 51:711, 1970.

21

6. Freedman L, Munro RH: Abduction of the arm in scapular plane: scapular and glenohumeral movements. J Bone Joint Surg 18A:1503, 1966. 7. Fukuda K, Chen CM, Cofield RH, Chao EY: Biomechanical analysis of stability and fixation strength of total shoulder prostheses. Orthopedics 11:141, 1988. 8. Halder AM, Kuhl SG, Zobitz ME, et al: Effects of glenoid labrum and glenohumeral abduction on shoulder joint stability through concavity compression: An in-vitro study. J Bone Joint Surg 83A(7):1062-1069, 2001. 9. Howell SM, Galinat BJ, Renzi AJ, Marone PJ: Normal and abnormal mechanics of the glenohumeral joint in the horizontal plane. J Bone Joint Surg 70A:227, 1988. 10. Inman VT, Saunders M, Abbot LC: Observations on the function of the shoulder joint. J Bone Joint Surg 26:1, 1944. 11. Itoi E, Kuechle DK, Newman SR et al: Stabilizing function of the biceps in stable and unstable shoulders. J Bone Joint Surg 75B:546, 1993. 12. Itoi E, Motzkin NE, Brown AD et al: Intraarticular pressure of the shoulder. Arthroscopy 9:406, 1993. 13. Laumann U: Kinesiology of the shoulder joint. In Kölbel R, Helbig B, Blauth W (eds): Shoulder Replacement. Berlin, Springer-Verlag, 1987. 14. Lee SB, Kim KJ, O'Driscoll SW, et al: Dynamic glenohumeral stability provided by the rotator cuff muscles in the mid-range and end-range of motion. A study in cadaver. J Bone Joint Surg 82A(6):849-857, 2000. 15. Lippitt SB, Vanderhooft JE, Harris SL, et al: Glenohumeral stability from concavity-compression: A quantitative analysis. J Shoulder Elbow Surg 2:27, 1993.

22

16. Morrey BF, An KN: Biomechanics of the shoulder. In Rockwood C, Matsen R (eds): Shoulder. Philadelphia, WB Saunders, 1990. 17. Neers CS II: Articular replacement of the humeral head. J Bone Joint Surg 37A:215, 1955. 18. Nobuhara K: The Shoulder: Its Function and Clinical Aspects. Tokyo, Igaku-Shoin, 1987. 19. Poppen NK, Walker PS: Normal and abnormal motion of the shoulder. J Bone Joint Surg 58A:195, 1976. 20. Poppen NK, Walker PS: Forces at the glenohumeral joint in abduction. Clin Orthop 58:165, 1978. 21. Reeves B, Jobbins B, Flowers M: Biomechanical problems in the development of a total shoulder endoprosthesis. J Bone Joint Surg 54B:193, 1972. 22. Saha AK: Dynamic stability of the glenohumeral joint. Acta Orthop Scand 42:491, 1971. 23. Steindler A: Kinesiology of the Human Body under Normal and Pathological Conditions. Springfield, Charles C Thomas, 1955. 24. Uhthoff H, Piscopo M: Anterior capsular redundancy of the shoulder: Congenital or traumatic? J Bone Joint Surg 67B:363, 1985. 25. Walker PS: Human Joints and Their Artificial Replacements. Springfield, Charles C Thomas, 1977. 26. Walker PS: Some bioengineering considerations of prosthetic replacement for the glenohumeral joint. In Inglis AE (ed): Symposium on Total Joint Replacement of the Upper Extremity. St. Louis, CV Mosby, 1982, p 25.

23

Chapter 28 Shoulder Component Design and Fixation Robert H. Cofield John W. Sperling

IMPLANT DESIGN Shoulder implant design is a complex interplay among replacing cartilage surfaces, restoring anatomy, taking into account biomechanical testing and theory, recognizing the benefits and limitations of various materials, considering the manufacturing processes, perceiving marketing issues, and heeding surgeons' needs for relative ease of insertion leading to reproducibility in surgery and consistency in outcome. Much of the scientific focus on implant designing for the shoulder has centered around a better understanding of the variations in anatomy of the upper end of the humerus. Multiple studies have used direct measurements on bones and, often, various means of adjunctive imaging. A number of studies have shown the humeral head to be not quite spherical but very close to being so, with the humeral head radius varying between 19 and 32 mm.3 , 7 , 37 , 68 , 69 , 85 The thickness of the humeral head in various investigations has ranged from 12 to 24 mm, with averages from 15 to 20 mm.7 , 37 , 68 , 69 , 85 The humeral head inclination relative to the axis of the humerus has varied between 120 and 145 degrees, with averages of 130 to 135 degrees.7 , 37 , 67 , 69 , 85 Assessment of humeral head retroversion has been more complicated as the angle has been measured in comparison to the transepicondylar axis, a tangent to the trochlea, a tangent to the elbow, or with reference to the forearm. 1

Retrotorsion relative to the transepicondylar axis in various series has ranged from -5 to 60 degrees, with averages from 18 to 22 degrees.7 , 68 , 69 , 85 In surgery, the most applicable of these references for humeral retrotorsion would be to the axis of the forearm, and in the one study in which this was assessed, the average was 41 degrees.36 In relation to the top of the greater tuberosity, the uppermost point of the humeral head rests above the level of the tuberosity by a range of 3 to 20 mm, averaging 8 to 8.7 mm.37 , 65 As a number of prosthetic systems have developed a fixed relationship between the central axis of the humeral shaft and the center of the humeral head, “new” additional anatomic parameters have also been identified. The anteroposterior offset of the humeral head relative to the central axis of the humerus has ranged between 3 mm of anterior offset to 11 mm of posterior offset and has averaged between 2 and 5 mm of posterior offset.3 , 7 , 68 , 85 The medial-lateral offset of the humeral head center relative to the central axis of the humeral shaft has ranged between 3 and 14 mm of medial offset, with averages between 7 and 11 mm.7 , 54 , 67 The internal humeral canal diameter has been less commonly measured. In two studies, this ranged between 8 and 14 mm and averaged 11 to 12 mm.3 , 67 Considering all these various parameters, it is easy to understand that prosthetic systems replacing the humeral head may alter joint kinematics, and in this setting, that has been assessed by measuring the effect of various implants on the center of rotation of the humeral head.49 Typically in implant systems, the center of rotation is shifted upward and laterally.65

2

Glenoid size has been measured in four studies.20 , 37 , 38 , 53 The superior-to-inferior dimension ranges between 26 and 48 mm with averages between 34 and 40 mm. The anteroposterior dimension is highly variable, depending upon where the measurement is taken. The largest measurements have varied between 16 and 35 mm with averages between 24 and 29 mm. Saha recognized that the radius of curvature of the humeral head and the radius of curvature of the glenoid in a shoulder joint may vary somewhat, leading to a lack of complete conformity between the articular surfaces.70 In a recent study, the radius of curvature of the glenoid was on average 2.3 mm greater than the radius of curvature of the humeral head.37 These differences in radius of curvature have been particularly apparent when the respective bones are assessed. When the actual articular cartilage surfaces are analyzed, the surfaces are quite conforming.76 Biomechanical studies have indicated that the translations seen in a natural shoulder joint are best reproduced in reconstructed joints that have somewhat less conforming articulations.27 , 40 , 87 A higher degree of conformity and constraint directly affects the forces generated during testing of translation and rotation of the humeral head.2 , 61 , 75 Also, during translation, higher forces are recognized at the glenoid component as joint conformity increases.39 However, when assessing kinematics of the glenohumeral joint in a cadaveric model with an intact capsule and rotator cuff tendons, alterations in motion patterns were minimally affected by a reduction in congruity between the articular surface prosthetic components—the sizes of the components inserted had a much more dominant affect on altering the joint kinematics.34

3

The material properties of polyethylene must also be considered when the curvature of the glenoid is altered relative to the humerus. An increasing amount of “mismatch” decreases contact area and increases contact pressure. For a load approximating body weight, contact stress exceeds yield stress for polyethylene when the radial mismatch is greater than three millimeters.54 One can see from the preceding paragraphs that there are a great variety of anatomic and biomechanical factors to be considered. This may lead to consideration of quite complex implant systems; however, the complexity of design may generate additional unanticipated problems, and the general admonition is to avoid components with multiple parts, if at all possible. For example, modularity of implant systems has been well accepted in the orthopaedic community to facilitate implant insertion, to aid in revision surgery, and to engender a manageable amount of implant inventory. A number of studies have been reported attesting to the safety and efficacy of modular humeral components.18 , 23 , 33 However, in spite of great care taken in prosthetic design, there are occasional dissociations of modular humeral head or glenoid components, and such dissociations have been reported.4 , 14 , 19 P.259

A SHOULDER ARTHROPLASTY SYSTEM For more than 20 years, the various components of shoulder implant design (Smith and Nephew, Memphis, Tennessee) have been carefully studied. Many things must be considered,

4

as outlined in Table 28.1. These must balance the many factors contributing to implant design. The surfaces must be replaced with materials having acceptable wear characteristics. Anatomy must be respected, as must biomechanical theory and testing. Competing ideas of simplicity versus complexity must be mated to create the ease of insertion that leads to reproducibility during surgery. This implies that some portions of the design will be near the mean of humeral variability, while others will vary in size or shape to match the spectrum of human dimensions. A consideration of the humeral head reveals that the radius of curvature varies somewhat between anatomic specimens but not dramatically. To avoid undue complexity, we have selected a constant radius of curvature for the humeral head that is in the midrange of anatomic values. By treating the glenoid in the same manner, it is possible to match any humeral head with any glenoid. Additionally, to aid in the potential need for revision surgery, the radius is also equal to that of the implant that has been used most commonly over time (Neer II, 3M, Saint Paul, Minnesota). On the other hand, humeral head sizes vary considerably, and to obtain the best tension in the soft tissues and to address ample mobility while respecting stability,15 head sizes should vary, and their variability should be intuitively understandable. The system has included a proportionate increase in thickness and width of the humeral heads, increasing by 2 mm increments in diameter and height for each larger implant size within the normal range of humeral head sizes. The system has always included a medial offset relative to the axis of the humeral shaft. Over time, it has not included a means to address anterior or posterior offset unless the humeral stem is

5

eccentrically cemented in the humeral canal. Although I believe that these issues are seldom important in shoulder arthroplasty, additional sets of humeral heads have been developed to make it possible to have additional anterior, posterior, or medial offset in selected cases. In a modular humeral head system, the tapered junction must be secure, and it seems reasonable to use a taper design that has been proved in large numbers of hip joint replacements. There must be a simple means to separate the humeral head from the stem. Extraction slots on the undersurface of the humeral head were selected to accomplish this, and a simple wedgeshaped removal tool can do the job. TABLE 28.1 CONSIDERATIONS IN SHOULDER IMPLANT DESIGN

Humeral head

Radius of curvature

Thickness and width

Offsets

Head-stem fixation

Extraction capability

6

Shape

Length(s)

Width(s)

Fins

Suture holes

Surface finish/fixation methods

Humeral instrumentation

Resection guide

Drills, reamers

Trials

Impaction, distraction device

Humeral component materials

7

Shape

Sizes (height and width)

Thickness

Surface curvatures

Pegs/keel

Surface finish/fixation methods

Glenoid instrumentation

Guides

Drills

Reamers

Router

Rasps/sizers

8

Pusher

Glenoid component materials

Instrument cases

Organized

Sequenced (a la Charnley)

The design of the humeral stem is critical. A single angle of inclination of the humeral head relative to the shaft has been selected, approaching the mean of this angle in human studies. This angle is slightly greater than that of the anatomic neck relative to the shaft and has the added positive effects of preserving humeral metaphyseal bone, creating the opportunity for tissue ingrowth fixation rather than cement fixation alone, and eliminating the potential for filling the inferior aspect of the glenohumeral joint with the prosthetic humeral head and thereby limiting overhead movement. A rather narrow, cylindrical stem preserves bone of the proximal humerus, saves space for tuberosity positioning and adjunctive bone grafting, and facilitates bone preparation with cylindrical cutting tools. The standard length implant must be long enough to reach the proximal end of the cylindrical humeral isthmus with its strong cortical bone. Longer stem lengths should be available to address distally extending

9

fractures or oncologic problems. There should only be a minimal proximal expansion of the humeral stem in order to preserve the metaphyseal humeral bone and to allow for off axis insertion, in cases of old trauma with malunion and other more unusual situations. The proximal portion of the stem contains four fins for rotational stability, with suture holes in all fins for additional security in tuberosity attachment. The stem diameter should vary in understandable amounts, and this system increases 2 mm in diameter for each larger component. For the surface finish, it is important to limit texturing to the metaphyseal region and, if possible, take advantage of tissue ingrowth instead of simple ongrowth in this region. The more distal aspect of the stem should be smooth, preferably polished as in this implant, for use with cement and for easy extraction of implants inserted with or without cement. The humeral instruments should allow carpenter-like fitting for the implant. This includes a resection guide that uses both intramedullary and extramedullary referencing, cylindrical humeral reamers, and adjunctive drills for preparation of harder bone. The reamers and drills should exactly equal implant size and have clear depth markings. Trial components should exactly reproduce the implants, and stem extensions should be available for trials of longer humeral stems. There should be a strong impaction and distraction device for the trial and real implants. The trial implants should have a metaphyseal plate to protect the exposed cancellous bone P.260

during glenoid preparation. Humeral head trials should fit the stem trials and the real implant stems (Fig. 28.1).

10

FIGURE 28.1 A: Humeral component with head and stem impacted together. B: Radiograph of humeral component in place, as a part of total shoulder arthroplasty. Note: The humeral calcar should be trimmed to avoid humerus-glenoid component impingement.22

11

FIGURE 28.2 Glenoid component. A: Keel design. B: Peg design. C: Tissue ingrowth design.

There are several materials that can be considered to construct the various parts of a humeral component. These 12

include stainless steel, chrome-cobalt, titanium, and ceramics. For this system, chrome-cobalt has been selected for both the humeral heads and the stems. The glenoid component should also include a variety of options. The most useful glenoid component is made of all high-density polyethylene, and, in this system, it comes in three sizes. To reduce forces across the glenoid and improve joint kinematics, the glenoid radius of curvature is 2 mm greater than the humeral component radius of curvature and is constant throughout system sizes.1 The undersurface of the component is curved, textured, and there are limited number of slots and holes to improve glenoid keel fixation in the bone cement.1 , 79 Additionally, pegged polyethylene components are available. The pegs maintain the area of contact between the implant and the cement. They do allow an easier and more reproducible insertion technique43; however, there is a reduction in the mass of polyethylene and some lingering concern about glenoid component strength (Fig. 28.2). An interesting P.261

biomechanical study has suggested that a pegged component is better for normal bone, while a keeled component has a more favorable distribution of stresses in softer bone.41 Using similar instruments, there is also a pegged metalbacked tissue ingrowth glenoid component in standard and small sizes for use in special situations, currently limited to shoulders in which there is a moderate amount of medial glenoid bone erosion that would preclude secure fixation with all polyethylene keel or peg designs.

13

Glenoid instruments include guides for preparation of the pegs or keel, three sizes of reamers to precisely prepare the subchondral plate, drills to prepare the holes for the pegs, a router to prepare the slot for the keel, and keel and peg rasps/sizers to finish the preparation of the bone within the glenoid neck. A pusher is available to firmly seat the glenoid component and to hold it in position while the bone cement is hardening.

FIGURE 28.3 The various humeral head sizes implanted in 562 shoulders.

14

FIGURE 28.4 The three types of humeral heads implanted between July 2001 and July 2004. All are available in head diameters 36 to 50 mm (Fig. 38-3). The standard head (center), 136 used. The 3 to 5-mm eccentric head (left), 151 used. The offset head 3 to 5-mm thicker (right), 158 used.

15

FIGURE 28.5 The various humeral stem sizes implanted in 507 shoulders.

16

FIGURE 28.6 The various glenoid sizes implanted in 302 shoulders.

The system includes well-organized instrument cases: a case for humeral preparation, a case containing humeral trials, a case containing extra humeral preparation items for longer stems or extra-large heads, an instrument tray with added retractors, and a glenoid tray. As can be seen from the preceding discussion, in constructing an implant system, many points are considered; in total, approximately 40 or 50 items need in-depth consideration when designing humeral and glenoid implants and the adjunctive instrumentation. The graphs display the distribution of humeral head sizes, humeral stem sizes, and the sizes of glenoid components that have been used recently (Figs. 28.3, 28.4, 28.5 and 28.6). It can be easily seen, as would be anticipated with variations in humeral size and anatomy, that a variety of component sizes have been used, with the most commonly used components in the mid ranges of bone size. P.262

COMPONENT FIXATION There are a number of areas that should be considered on this topic. These include finite element modeling and analysis, mechanical pullout testing, results of clinical series, reports on implantation technique, and radiographic analysis of implant security. Several authors have undertaken finite element analysis of the glenoid and the humerus.21 , 16 , 63 , 64 , 82 Preservation of

17

part of the strong, subchondral bone is important,31 as is bone quality.50 Of importance to component fixation, the analysis of the glenoid clearly indicates that a cemented polyethylene component most closely replicates the stress distribution seen in a normal glenoid. If metallic materials are introduced, the analysis is greatly distorted by the presence of the metal, particularly when the metal contacts cortical bone. Mechanical pullout tests have been done with bone or bone simulated by various materials such as variable densities of polyurethane.28 , 48 Although one would initially believe that this form of testing might have strong relevance to implant design and fixation, this has not been proved to be the case. The forces and displacements determined before and after many cycles of loading show very little difference, and the force to displacement (distraction) is most dependent upon the material properties of the implant system. Results are most notably affected by having metal as a part of the fixation for the implanted glenoid—the metal, of course, being much more resistant to distraction than polyethylene. Also, the thickness of the cement mantle will play a role with a slightly thicker cement mantle improving pullout force.57 Many clinical series have, as an adjunct to reporting results, assessed the relatively high frequency of glenoid lucent lines, and the quite low necessity for revision surgery for component loosening.9 In a similar fashion, my colleagues and I assessed 89 shoulders with an average 9.7 years of follow-up (range, 5-17 y).83 These patients had surgery between 1975 and 1981 and included the diagnoses of osteoarthritis, rheumatoid arthritis, and posttraumatic arthritis. The survival curve illustrated the need for revision

18

surgery to be quite low. Notably, over this approximately 10year average follow-up period, only 5.6% of the glenoids had clinical loosening, and 1.8% of the humeral components had clinical loosening. We did, however, notice in the assessment of our series that there was a significant frequency of radiographic change surrounding both components. We felt that 44% of the glenoid components were radiographically loose; of the humeral components, 45%, almost all of which were press-fitted, were radiographically loose. This and other studies have led us to the conclusion that assessment of radiographic characteristics of components is most sensitive in distinguishing between components that behave favorably and those that might be predisposed to clinical loosening.10 , 13 , 35 , 42 , 56 , 84 TABLE 28.2 RADIOGRAPHIC ASSESSMENT OF SHOULDER ARTHROPLASTY

No. shoulders

Mean followup (Years)

No. “At Risk” for loosening (%)

Cemented Neer II glenoid

81

4.1

31

Press-fitted humerus

72

4.1

56 (pressfit)

Cemented humerus

43

6.6

2

Studies

1.

2.

19

3.

4.

Ingrowth glenoid

62

4.6

6.5

Ingrowth humerus

62

4.6

10

Secondgeneration, cemented glenoid

88

3.5

14

Ingrowth humerus

73

3.5

4

To further this end, we developed a system for radiographic assessment of glenoid and humeral components, and then have applied this in four clinical series. The basic format was to have comparative radiograph views done early (within 2 months of surgery) and late (those done at most recent follow-up). Radiographic analysis would include a zonal analysis surrounding the glenoid component. We currently favor five zones for pegged components and for keeled components. The humeral interface is divided into eight zones, very similar to that used for the femoral component in hip arthroplasty. The locations of the lucent lines are noted, and their thickness is measured to 0.5 mm. Three observers then assess the early and late radiographs and offer their opinion about whether or not there has been a shift in component position for either the glenoid or the humeral component. Earlier, measurements of radiographs were done to determine whether a change in position had occurred.

20

These measurements correlated closely with the opinions of the independent observers, and the measurements have been discontinued. In addition to collecting the raw data, we then developed empirical criteria when a component might be radiographically “at risk” for clinical problems.60 These included a glenoid component that had a complete lucent line surrounding the implant, some part of which was 1.5 mm or greater in thickness, or a glenoid component that was judged to have shifted in position by two of three or three of three observers. Similarly, a humeral component was judged to be at risk for clinical problems if lucent lines were in three or more zones and were greater than 2 mm in width, or if two of three or three of three of the independent observers saw a shift in humeral component position. The four clinical studies are outlined in Table 38.2. The first study on the cemented Neer II glenoid component and the press-fit humeral component occurred in patients operated on between 1981 and 1985.62 There were one surgeon and a consistent surgical technique. This included power burring for surface preparation on the glenoid, burring the keel slot without guides, partially preserving the subchondral plate and undermining it, irrigating with bulb lavage and sponge packing for cleaning the glenoid, placing the cement in the glenoid and packing it with pressure, then placing the component backed with cement into the bone58 and holding it in position with the thumb. In this group of patients, 72 humeral components were press-fitted, and 9 were cemented in place. On radiographic analysis, 31% of the glenoid components were judged to be at risk by these criteria, and, surprisingly,

21

56% of the press-fitted humeral components were judged to be at risk.72 The second study included a clinical group, operated on between 1976 and 1987, who had a cemented humeral P.263

component as a part of hemiarthroplasty or total shoulder replacement.71 Only one humeral component (2%) exhibited radiographic features of at-risk magnitude. Shoulders undergoing placement of an ingrowth total shoulder arthroplasty between 1989 and 1992 were assessed.77 Strikingly, only four glenoid components (6.5%) and six humeral components (9.7%) were judged to be radiographically at risk. Most recently, we radiographically assessed the second generation of total shoulder arthroplasty.5 These procedures were done between 1990 and 1995. The improved techniques included the availability of a variety of glenoid component sizes and variations, glenoid instruments, use of pulsatile lavage for cleansing the glenoid neck, direct use of cement pressurization into the glenoid keel slot, component impaction and holding with an insertion device,60 and better balancing of the joint using various soft tissue releases and tightening procedures. In this patient group, 12 (14%) exhibited at-risk changes of the glenoid component, and 3 of 73 tissue ingrowth humeral components (4%) exhibited radiographic changes of at-risk level. Thus, for this more complex and systemic radiographic assessment of total shoulder arthroplasty, we were able to conclude that the radiographic changes surrounding the earlier implant design and the earlier implant technique are

22

potentially problematic for later clinical problems. Tissue ingrowth surfaces for the glenoid are promising for component fixation of bone but, of course, are currently questionable relative to accelerated polyethylene wear. The radiographic changes surrounding the second-generation cemented glenoid components are less than half of those seen in the early series, but they still cause concern. When we have more years of follow-up, we may be able to assess the radiographic features of total shoulder arthroplasties with a mismatch of the humeral and glenoid radii of curvatures, and we may then be able to judge the effect of humeral modularity on joint kinematics—as reflected in the radiographic changes seen. Three or four years after that, cemented, pegged glenoid components can be assessed. Assessment of the humeral components has led us to conclude that surgeons should be wary of the use of press-fit stems. The incorporation of tissue ingrowth (perhaps more substantial texturing) has much improved the radiographic features surrounding the humeral component. However, it is clearly recognizable that cementing the humeral component yields the best radiographic features and, quite likely, the most durable fixation for the humeral component. Having assessed these things for a typical arthritic shoulder undergoing shoulder arthroplasty, we currently recommend an all-polyethylene cemented glenoid component whenever practically possible, with use of advanced surgical techniques. We currently also continue to use the tissue ingrowth humeral component with the tissue ingrowth surfaces limited to the undersurface of the plate for the trunion and on the upper few centimeters of the stem,

23

contacting only the humeral metaphysis and not diaphyseal bone. Initial fixation must, of course, be secure. Early response of the bone to the prosthetic implants and the cement must maintain the initial strong fixation. An important limiting issue is our response to wear particles over time.86 It seems probable most implant loosening is due to bone resorption as a consequence to this wear. We continually strive for better joint kinematics to decrease wear. We must also be searching for new materials with better wear characteristics. Various metal-backed glenoid components are being introduced to improve the security of the initial fixation, but we must remember this will increase stresses in the polyethylene82 and likely increase polyethylene wear.6 , 51 , 78 , 80

EVOLVING DESIGN CONCEPTS As mentioned earlier, there are many considerations in shoulder implant design (Table 28.1). The designer or design team must decide which of these items will be constructed as the mean or average of human anatomy and which will be variable as a part of the implant system. For example, in addition to the implant characteristics outlined earlier, some contemporary implant systems have also included variability in the inclination of the osteotomy of the humeral head and correspondingly the inclination of the upper end of the humeral stem to give the surgeon even more options at the time of the operation. The “Bio-Modular” shoulder system (Biomet, Warsaw, Indianna) in evolving to the “Comprehensive” shoulder system has altered both the humeral and glenoid components. The humeral component now comes in three lengths: mini, standard, and revision.

24

They are in 1-mm diameter increments. They have a proximal plasma sprayed porous coating and are polished distally. There is a standard 45-degree anatomic neck angle. The humeral stem continues to have a reverse Morris taper. There are 46 different humeral stemmed implants to accommodate this substantial variability. A taper adapter, a third part of the humeral implant, has been intercalated between the humeral stem and the humeral head. This part has two male taper components and when mated with the 17 sizes of humeral heads that have the female part of the trunion with slight offset allows the surgeon to have an infinite amount of offset between 0.5 and 4.5 mm. The glenoid component in this system has also been modified to include not only the traditional all-polyethylene glenoid component with rather typical posts but, in addition, glenoid components with a central post that allows for compression fitting while cementing the other posts or a porous titanium central peg that allows for bone ingrowth opportunities while the peripheral pegs are cemented. So, as an example, one can easily recognize from the brief outline above that this system has evolved to allow the surgeon to have more flexibility but also the implant system does add complexity—and for the humeral component an additional component articulation. A further example of increasing adaptability and complexity is the PRMOS shoulder system (Smith and Nephew, Inc., Memphis, Tennessee). In this system, the humeral component has four major parts, an ingrowth humeral stem in nine sizes, a metaphyseal body that will allow the surgeon to rotate this part on the stem and also to adjust the height, and an inclination set that is attached to the body that can vary the position of the male part of the trunion for the humeral head

25

in 12 degrees in any direction. On top of this is seated an eccentric humeral head that comes in 18 sizes. One can appreciate how the complexity of this system has increased, yet it allows greater versatility in reconstructing the upper end of the humerus with its articulating surface. Both of the more complex implant system examples outlined above have, as a part of their systems, developed the capability of converting these implants to a reverse type shoulder implant without removing a firmly fixed humeral stem. For cases with significant deformity in the upper humerus, these implants may be essential, but for the more typical patient with loss of cartilage and minimal bony alteration, the advantages of system complexity may not necessarily be realized either in laboratory testing12 or in patient outcomes.55

Resurfacing Arthroplasty Using a cup to resurface the arthritic surface of the humeral head is very intriguing. Occasionally this concept was utilized in the 1970s and early 1980s, but it was not until the P.264

mid-1980s this was developed to the extent that this type of implant became more readily available for general use.47 The central concept is to mimic normal anatomy, to save the bone and by virtue of minimal bone resection, reserve humeral length, humeral offset, and varus/valgus inclination. Although this component has been fixed in place with bone cement, it is more commonly press-fitted or formed with a textured surface that will allow bony ongrowth or with a hydroxyapatite covering that may in fact allow bony ingrowth. Being applied

26

to the surface, this eliminates reaming of the humeral canal that may be especially undesirable in those with previous fracture deformity or old osteomyelitis. It would also lessen the possibility of periprosthetic humeral implant fractures46 (Fig. 28.7). Another advantage should be that it is simple to insert and can be performed not only by a deltopectoral but also by a more limited anterosuperior surgical approach. Newer models have a variety of humeral head sizes available, but it would be difficult to alter the size more than a minor amount—as one is mimicking the normal size of the humeral head. Ample soft tissue releases must still be performed in the presence of contractures but the adjunctive lengthening obtained by decreasing the size of the humeral head will not be possible. There must be an adequate quantity and quality of bone in the humeral head to support this implant. It is said that if more than 60% of the humeral head remains, the use of this implant is practically possible.44 There are several negative features of this type of implant. If one wishes to place a glenoid component, glenoid exposure is limited. In line with the above comments about sizing and tissue releases, there is a mild but definite tendency for increasing the medial to lateral humeral offset when using this type of implant.26 , 81

27

FIGURE 28.7 A 64-year-old woman with rheumatoid arthritis who previously had left total elbow arthroplasty with bone cement extending up the humerus to near the humeral head. She had a fracture above the elbow prosthetic stem that was not healing. She also had severe arthritis of the glenohumeral joint with stiffness and central glenoid erosion. With the humeral canal filled with cement and fractured, it was elected to internally fix the humeral shaft fracture, supplementing the fracture site with an allograft strut. The glenohumeral joint was then released of scar, and the humeral head was resurfaced with the cup type prosthetic replacement.

In terms of component fixation, occasional component loosening is observed, as is shift in implant position or the presence of a complete 2-mm-thick lucent line. However, these findings are unusual in the series reported to date.

28

Reverse Designs A number of reverse designs were formulated initially when it was thought that the majority of patients requiring shoulder arthroplasty had both arthritis and deficiencies of the rotator cuff. When it was discovered that these implants had a high failure rate and the majority of patients who required shoulder arthroplasty had arthritis but a rotator cuff that was adequate to apply stability, reverse type implants fell from favor. However, in the mid 1980s, Grammont29 rethought the issue and believed that one could create a viable implant for those patients with the combined pathology if one moved the center of rotation of the reverse type implant medially to be near the glenoid surface. This would decrease stresses on the fixation of the glenoid component and, at the same time, increase the lever arm of the deltoid muscle to provide more strength for arm elevation. His early design has been modified on a number of occasions and is now represented by the DELTA/Xtend (DePuy Orthopedics, Inc., Warsaw, Indianna). The Aequalis reversed shoulder prosthesis (Tornier, Stafford, Texas) has many similarities. Both provide a fixed fulcrum for movement and have a large diameter glenosphere with an exactly matching polyethylene humeral cup. Both include a central glenoid base plate and peripheral fixation screws, at least two of which are angulated and locking. Two others are compressive. The inclination of the humeral component is 155 degrees, and unlike the press-fitted ingrowth, glenoid component is typically cemented within the humerus. The design rationale and biomechanics of this type of implant system have been clearly formulated.8

29

A slightly different approach was taken in North America, utilizing the initial Grammont concepts but modifying them slightly.24 , 25 In this system, a central screw was used to compress the glenoid base plate against the glenoid, and parallel locking screws, rather than divergent screws, were used for supplementary glenoid base plate fixation. A variety of sizes of glenospheres and offsets were offered, varying from 32 to 40 mm in diameter and from 0 to 10 mm in offset. When there was optimum glenoid bone quality, slightly smaller glenospheres could be used as well as those with a somewhat lateral offset to improve range of motion and perhaps functional strength. When glenoid bone quality was less adequate, one could select the glenosphere with a medialized center of rotation, and when instability was thought to be an important issue, a larger glenosphere could be selected. This system also had thinner humeral components most appropriate for smaller people, particularly elderly women who might require this type of implant system. Initial analyses of this newer implant system have focused in several areas. The first is outcomes related to patient selection. It has been recognized that the best outcomes occur in those with the classic rotator cuff tear arthropathy but with ample glenoid bone stock.74 , 45 It is also felt to be quite useful for the treatment of failed anatomic type arthroplasties with instability and associated rotator cuff deficiency.48 Much less common indications include patients with rheumatoid arthritis and severe rotator cuff lesions66 or for elderly patients with extremely comminuted proximal humerus fractures.11 However, with continuing length of follow-up, there is still the P.265

30

strong admonition that this type of implant should be used rather exclusively in patients over 70 years of age and with low functional demands.30 Improving glenoid component fixation has required a more in-depth study of the anatomy of the scapula49 and defining most precisely the locations for supplemental screw fixation. Biomechanical assessment of implants with proper screw placement suggests that initial fixation for the glenoid base plate is clearly adequate.32

FIGURE 28.8 A: An older woman with rotator cuff tear arthropathy who had the more traditional type of reverse shoulder arthroplasty with the center of rotation of the glenosphere slightly medial to the face of the glenoid. The glenoid is fixed in place by a central peg and four diverging screws, two of which are locked into the glenoid base plate. The humeral component is cemented. B: A reverse type shoulder arthroplasty with a slightly more lateral center of rotation of the glenosphere and a larger glenosphere both to achieve stability and enhanced rotational movements. The patient is a piano player who requires substantial rotational movements and yet also requires stability related to her complex proximal humeral fracture, subsequent proximal humeral bone loss, and replacement of the proximal bone loss with a proximal

31

humeral allograft. In this model, the glenoid base plate is fixed in position with a central compressive screw. Additional fixation is obtained with four peripheral locking screws in parallel alignment. The humeral component is cemented in position through the allograft and into native bone.

This implant concept and newly formulated designs will offer expanded opportunities for improvement of patient outcomes for certain conditions; however, it will also lead to more frequent complications than might be expected with more time-proven designs and concepts.52 In addition to glenoid or humeral component loosening or dissociation of these multiply-linked components,74 , 17 other things have surprisingly occurred including acromial stress fractures and unexplained cases of glenohumeral instability. An important new complication has been inferior scapular notching, some of which is attributable to encroachment of the medial aspect of the humeral component into the junction of the inferior aspect of the glenoid and axillary border of the scapula. An extension of this notching superiorly must be related to a polyethylene damage and osteolysis.59 Predictors of scapular notching include the angle between the glenosphere and the scapular neck, the craniocaudal position of the glenosphere and the amount of glenosphere offset.73 There is much to be learned about the nuances of the application of this implant system, and one could anticipate an entire chapter related to the reverse implant system in the next edition of this textbook (Fig. 28.8A,B).

References 1. Anglin C, Wyss UP, Nyffeler RW, Gerber C: Loosening performance of cemented glenoid prosthesis design pairs. Clin Biomech 16(2):144-150, 2001.

32

2. Anglin C, Wyss UP, Pichora DR: Shoulder prosthesis subluxation: theory and experiment. J Shoulder Elbow Surg 9:104, 2000. 3. Ballmer FT, Sidles JA, Lippitt SB, Matsen FA: Humeral prosthetic arthroplasty: Surgically relevant considerations. J Shoulder Elbow Surg 2:296, 1993. 4. Blevins FT, Deng X, Torzilli PA, et al: Dissociation of modular humeral head components: A biomechanical and implant retrieval study. J Shoulder Elbow Surg 6:113, 1997. 5. Mileti J, Boardman ND III, Sperling JW, Cofield RH, Torchia ME, O'Driscoll SW, Rowland CM: Radiographic analysis of polyethylene glenoid components using modern cementing techniques. J Shoulder Elbow Surg 13(5): 492-498, 2004. P.266

6. Boileau P, Avidor C, Krishnan SG, et al: Cemented polyethylene versus uncemented metal-backed glenoid components in total shoulder arthroplasty: A prospective, double-blind, randomized study. J Shoulder Elbow Surg 11(4):351-359, 2002. 7. Boileau P, Walch G: The three-dimensional geometry of the proximal humerus. Implications for surgical technique and prosthetic design. J Bone Joint Surg 79-B:857, 1997. 8. Boileau P, Watkinson DJ, Hatzidakis AM, Balg F: Grammont reverse prosthesis: Design, rationale, and biomechanics. J Shoulder Elbow Surg 14(1S):147S-167S. 9. Brems J: The glenoid component in total shoulder arthroplasty. J Shoulder Elbow Surg 2:47, 1993.

33

10. Brostrom LA, Kronberg M, Wallensten R: Shoulder the glenoid be replaced in shoulder arthroplasty with an unconstrained Dana or St. Georg prosthesis? Annales Chirurgiae et Gynaecologiae 81:54, 1992. 11. Bufquin T, Hersan A, Hubert L, Massin P: Reverse shoulder arthroplasty for the treatment of three- and four-part fractures of the proximal humerus in the elderly. A prospective review of 43 cases with a short-term follow-up. J Bone Joint Surg 89B:516-520, 2007. 12. Churchill RS, Kopjar B, Fehringer EV, et al: Humeral component modularity may not be an important factor in the outcome of shoulder arthroplasty for glenohumeral osteoarthritis. Am J Orthop 34(4):173-176, 2005. 13. Cofield RH: Uncemented total shoulder arthroplasty. Clin Orthop 307:86, 1994. 14. Cooper RA, Brems JJ: Recurrent dissembly of a modular humeral prosthesis. J Arthroplasty 6:375, 1991. 15. Couteau B, Mansat P, Estivalezes E, et al: Finite element analysis of the mechanical behavior of a scapula implanted with a glenoid prosthesis. Clin Biomech 16(7):566-575, 2001. 16. de Leest O, Rozing PM, Rozendaal LA, van der Helm FCT: Influence of glenohumeral prosthesis geometry and placement on shoulder muscle forces. Clin Orthop 330:222, 1996. 17. De Wilde L, Walch G: Humeral prosthetic failure of reversed total shoulder arthroplasty: A report of three cases. J Shoulder Elbow Surg 15(2):260-264, 2006. 18. Dines DM, Warren RF: Modular shoulder hemiarthroplasty for acute fractures. Clin Orthop 307:18-1994.

34

19. Driessnack RP, Ferlic DC, Wiedel JD: Dissociation of the glenoid component in the Macnab/English total shoulder arthroplasty. J Arthroplasty 5:15, 1990. 20. Ebraheim NA, Xu R, Haman SP, et al: Quantitative anatomy of the scapula. Am J Orthop 29:287-292, 2000. 21. Ehnes DL, Stone JJ, Cofield RH, An KN: Analysis of the shoulder implant. Biomed Sci Instrum 36:129, 2000. 22. Favre P, Moor B, Snedeker JG, Gerber C: Influence of component positioning on impingement in conventional total shoulder arthroplasty. Clin Biomech 23(2):175-183, 2008. 23. Fenlin JM, Ramsey ML, Allardyce TJ, Brierman BG: Modular total shoulder replacement: design rationale, indications and results. Clin Orthop 7:37, 1994. 24. Frankle M, Levy JC, Pupello D, et al: The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency: A minimum two-year follow-up study of sixty patients surgical technique. J Bone Joint Surg 87A:1697-1705, 2005. 25. Frankle M, Levy JC, Pupello D, et al: The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency: A minimum two-year follow-up study of sixty patients surgical technique. J Bone Joint Surg 88A(Suppl 1, Part 2):178-190, 2006. 26. Fuerst M, Fink B, Rüther W: The DUROM cup humeral surface replacement in patients with rheumatoid arthritis. J Bone Joint Surg 89A: 1756-1762, 2007. 27. Fukuda K, Chen CM, Cofield, RH, Chao EYS: Biomechanical analysis of stability and fixation strength of total shoulder prostheses. Orthopedics 11:141, 1988. 28. Gartsman GM, Russell JA, Gaenslen E: Modular shoulder arthroplasty. J Shoulder Elbow Surg 6:333, 1997.

35

29. Grammont P, Trouilloud P, Laffay J, Deries X: Etude et réalisation d'une nouvelle prosthèse d'épaule. Rhumatologie 39:407-418, 1987. 30. Guery J, Favard L, Sirveaux F, et al: Reverse total shoulder arthroplasty. Survivorship analysis of eighty replacements followed for five to ten years. J Bone Joint Surg 88A(8):1742-1747, 2006. 31. Gupta S, van der Helm FC, van Keulen F: Stress analysis of cemented glenoid prostheses in total shoulder arthroplasty. J Biomech 37(11):1777-1186, 2004. 32. Harman M, Frankle M, Vasey M, Banks S: Initial glenoid component fixastion in “reverse” total shoulder arthroplasty: A biomechanical evaluation. J Shoulder Elbow Surg 14(1 Suppl S):162S-167S, 2005. 33. Harryman DT, Sidles JA, Harris SL, et al: The effect of articular conformity and the size of the humeral head component on laxity and motion after glenohumeral arthroplasty. A study in cadavera. J Bone Joint Surg 77A:555, 1995. 34. Havig MT, Kumar A, Carpenter W, Seiler JG: Assessment of radiolucent lines about the glenoid. J Bone Joint Surg 70A:428, 1997. 35. Hernigou P, Duparc F, Filali C: Humeral retroversion and shoulder prosthesis. Revue de Chirurgie Orthopedique et Reparatrice de l Appareil Moteur 81:419, 1995. 36. Iannotti JP, Gabriel JP, Schneck SL, et al: The normal glenohumeral relationships. An anatomical study of 140 shoulders. J Bone Joint Surg 74-A:491, 1992. 37. Jobe CM, Iannotti JP: Limits imposed on glenohumeral motion by joint geometry. J Shoulder Elbow Surg 4:281, 1995.

36

38. Karduna AR, Williams GR, Iannotti JP, Williams JL: Total shoulder arthroplasty biomechanics: a study of the forces and strains at the glenoid component. J Biomech Eng 120:92, 1998. 39. Karduna AR, Williams GR, Williams JL, Iannotti JP: Glenohumeral joint translations before and after total shoulder arthroplasty. J Bone Joint Surg 70-A:1166, 1997. 40. Kelleher IM, Cofield RH, Becker DA, Beabout JW: Fluoroscopically positioned radiographs of total shoulder arthroplasty. J Shoulder Elbow Surg 1:306, 1992. 41. Lacroix D, Murphy LA, Prendergast PJ: Three-dimensional finite element analysis of glenoid replacement prostheses: A comparison of keeled and pegged anchorage systems. J Biomech Eng 122(4):430-436, 200. 42. Lacroix D, Prendergast PJ: Stress analysis of glenoid component designs for shoulder arthroplasty. Proceedings of the Institution of Mechanical Engineers. Part H - J Eng Med 211:467, 1997. 43. Lazarus MD, Jensen KL, Southworth C, Matsen FA III: The radiographic evaluation of keeled and pegged glenoid component insertion. J Bone Joint Surg 87A(7):1174-1182, 2002. 44. Levy J, Frankle M, Mighell M, Pupello D: The use of the reverse shoulder prosthesis for the treatment o failed hemiarthroplasty for proximal humeral fracture. J Bone Joint Surg 89A(2):290-300, 2007. 45. Levy JC, Virani N, Pupello D, Frankle M: Use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty in patients with glenohumeral arthritis and rotator cuff deficiency. J Bone Joint Surg 89B(2):189-195, 2007.

37

46. Levy O, Copeland SA: Cementless surface replacement arthroplasty (Copeland CSRA) for osteoarthritis of the shoulder. J Shoulder Elbow Surg 13:266-271, 2004. 47. Levy O, Copeland SA: Cementless surface replacement arthroplasty of the shoulder: 5 to 10 year results with the Copeland Mark-2 prosthesis. J Bone Joint Surg 83B(2):213221, 2001. 48. Levy O: Surface replacement arthroplasty, Chapter 56. In Zuckerman JD (ed): Advanced Reconstruction Shoulder. New York, AAOS, 2007, pp. 527-534. 49. Mallon WJ, Brown HR, Vogler JB III, Martinez S: Radiographic and geometric anatomy of the scapula. Clin Orthop 277:142-154, 1992. 50. Mansat P, Briot J, Mansat M, Swider P: Evaluation of the glenoid implant survival using a biomechanical finite element analysis: Influence of the implant design, bone properties, and loading location. J Shoulder Elbow Surg 16(3 Suppl):S79S83, 2007. 51. Martin SD, Zurakowski D, Thornhill TS: Uncemented glenoid component in total shoulder arthroplasty. Survivorship and outcomes. J Bone Joint Surg 87A(6):1284-1292, 2005. 52. Matsen FA III, Boileau P, Walch G, et al: The reverse total shoulder arthroplasty. J Bone Joint Surg 88A(3):660665, 2006. 53. Matsen FA III, Lippitt SB, Sidles JA, Harryman DT II: Practical Evaluation and Management of the Shoulder. Philadelphia, W.B. Saunders Company, 1994, pp. 181-198. 54. Maynou C, Petroff E, Mestdagh F, et al: Devenir clinique et radiologique des implants humeraux des arthroplasties d'epaule. Acta Orthopaedic Belgica 65:57, 1999.

38

55. Mileti J, Sperling JW, Cofield RH, et al: Monoblock and modular total shoulder arthroplasty for osteoarthritis. J Bone Joint Surg 87B(4):496-500, 2005. 56. Norris BL, Lachiewicz PF: Modern cement technique and the survivorship of total shoulder arthroplasty. Clin Orthop 328:76, 1996. 57. Nyffeler RW, Anglin C, Sheikh R, Gerber C: Influence of peg design and cement mantle thickness on pull-out strength of glenoid component pegs. J Bone Joint Surg 85B(5):748752, 2003. 58. Nyffeler RW, Meyer D, Sheikh R, et al: The effect of cementing technique on structural fixation of pegged glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 15(1):106-111, 2006. 59. Nyffeler RW, Werner CML, Simmen BR, Gerber C: Analysis of a retrieved Delta III total shoulder prosthesis. J Bone Joint Surg 86B(8):1187-1191, 2004. 60. O'Driscoll, SW, Wright TW, Cofield RH, et al: The glenoid problem. Radiographic assessment of the glenoid component in total shoulder arthroplasty. In Mansat P (ed): Protheses d'epaule. Expansion Scientifique Publication, 1999, p. 337. 61. Oosterom R, Rozing PM, Verdonschot N, Bersee HE: Effect of joint conformity on glenoid component fixation in total shoulder arthroplasty. Proceedings of the Institution of Mechanical Engineers. Part H: J Eng Med 218(5):339-347, 2004. 62. Orr TE, Carter DR: Stress analyses of joint arthroplasty in the proximal humerus. J Orthop Res 3:360, 1985. 63. Orr TE, Carter DR, Schurman DJ: Stress analyses of glenoid component designs. Clin Orthop 232:217, 1988. P.267

39

64. Pearl ML, Kurutz S: Geometric analysis of commonly used prosthetic systems for proximal humerus replacement. J Bone Joint Surg 81-A:660, 1999. 65. Pearl ML, Volk AG: Coronal plane geometry of the proximal humerus relevant to prosthetic arthroplasty. J Shoulder Elbow Surg 5:320, 1996. 66. Rittmeister M, Kerschbaumer F: Grammont reverse total shoulder arthroplasty in patients with rheumatoid arthritis and nonreconstructible rotator cuff lesions. J Shoulder Elbow Surg 10(1):17-22, 2001. 67. Roberts SN, Foley AP, Swallow HM, et al: The geometry of the humeral head and the design of prostheses. J Bone Joint Surg 73-B:647, 1991. 68. Robertson DD, Yuan J, Bigliani LU, et al: Threedimensional analysis of the proximal part of the humerus: Relevance to arthroplasty. J Bone Joint Surg 82-A:1594, 2000. 69. Saha AK: Recurrent anterior dislocation of the shoulder. A new concept. Calcutta, Academic Publishers, 1969, pp 9-10. 70. Sanchez-Sotelo J, O'Driscoll SW, Torchia ME, et al: Radiographic assessment of cemented humeral components in shoulder arthroplasty. J Shoulder Elbow Surg 10(6):524531, 2001. 71. Sanchez-Sotelo J, Wright TW, O'Driscoll SW, et al: Radiographic assessment of uncemented humeral components in total shoulder arthroplasty. J Arthroplasty 16(2):180-187, 2001. 72. Severt R, Thomas BJ, Tsenter MJ, et al: The influence of conformity and constraint on translational forces and frictional

40

torque in total shoulder arthroplasty. Clin Orthop 292:151, 1993. 73. Simovitch RW, Zumstein MA, Lohri E, et al: Predictors of scapular notching in patients managed with the Delta III reverse total shoulder replacement. J Bone Joint Surg 89A(3):588-600, 2007. 74. Sirveaux F, Favard L, Oudet D, et al: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg 86B(3):388-395, 2004. 75. Soslowsky LJ, Flatow EL, Bigliani LU, Mow VC: Articular geometry of the glenohumeral joint. Clin Orthop 285:181, 1992. 76. Sperling JW, Cofield RH, O'Driscoll SW, et al: Radiographic assessment of ingrowth total shoulder arthroplasty. J Shoulder Elbow Surg 9:507, 2000. 77. Stone KD, Grabowski JJ, Cofield RH, et al: Stress analyses of glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 8:151-1999. 78. Swieszkowski W, Bednarz P, Prendergast PJ: Contact stresses in the glenoid component in total shoulder arthroplasty. Proceedings of the Institution of Mechanical Engineers. Part H - J Eng Med 217(1):49-71, 2003. 79. Szabo I, Buscayret F, Edwards TB, et al: Radiographic comparison of flatback and convex-back glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 14(6):636-642, 2005. 80. Taunton MJ, McIntosh AL, Sperling JW, Cofield RH: Total shoulder arthroplasty with a metal-backed, bone-ingrowth

41

glenoid component. Medium to long-term results. J Bone Jonit Surg 90A(10):2180-2188, 2008. 81. Thomas SR, Sforza G, Levy O, Copeland SA: Geometrical analysis of Copeland surface replacement shoulder arthroplasty in relation to normal anatomy. J Shoulder Elbow Surg 14:186-192, 2005. 82. Torchia ME, Cofield RH, Settergren, CR: Total shoulder arthroplasty with the Neer prosthesis: long-term results. J Shoulder Elbow Surg 6:495, 1997. 83. Walch G, Boileau P: Morphological study of the humeral proximal epiphysis. In Proceedings of the European Society for Surgery of the Shoulder and Elbow. J Shoulder Elbow Surg 74-B (Suppl I):14, 1992. 84. Walker PS: Human Joints and Their Artificial Replacements. Springfield, Charles C. Thomas Publishers, 1977, p 351. 85. Wallace AL, Phillips RL, MacDougal, et al: Resurfacing of the glenoid in total shoulder arthroplasty. A comparison, at a mean of five years, of prostheses inserted with and without cement. J Bone Joint Surg 81-A:510, 1999. 86. Wirth MA, Agrawal CM, Mabrey JD, et al: Isolation and characterization of polyethylene wear debris associated with osteolysis following total shoulder arthroplasty. J Bone Joint Surg 81A(1):29-37, 1999. 87. Wuelker N, Schmotzer H, Thren K, Korell M: Translation of the glenohumeral joint with simulated active elevation. Clin Orthop (309): 193-200, 1994.

42

Chapter 29 Resurfacing Humeral Arthroplasty: Design, Considerations, and Fixation Kristofer S. Matullo Scott P. Steinmann

INTRODUCTION For those patients with total glenohumeral joint pathology and articular destruction, total shoulder arthroplasty is a reliable procedure with good long-term results. However, the solution for younger patients or a working population is more challenging. Procedures, such as resurfacing the humeral head with a stemmed hemiarthroplasty or even replacing a partial articular defect of the humeral head with allograft, remain potential options. Humeral head resurfacing is a newer option with promising results. This technique can also be combined with either biologic or polyethylene resurfacing of the glenoid, if articular destruction is present.

HISTORY Since Dr. Charles Neer's development of the humeral prosthesis, shoulder arthroplasty has been a surgical procedure for decades in the forms of either hemiarthroplasty or total shoulder replacement with good short- and long-term results. The newer idea of humeral head resurfacing allows for preserving humeral head bone stock for future surgical revision and may provide an ease of conversion to a stemmed implant without the need of cement removal or extraction of the humeral stem.

1

Recently, osteochondral defects within the humeral head of a limited size have been surgically treated with osteochondral resurfacing. Gerber and Lampert2 described their technique in four patients with chronic locked posterior humeral dislocations. They utilized this technique when there was 40% to 50% involvement of a humeral head with the remainder of the surface having good articular cartilage. Using a deltopectoral approach, the humeral head was reconstructed with cadaveric cryopreserved femoral heads. At an average follow-up of 5.5 years, stability was restored to each patient, and radiographs demonstrated no failure of fixation at the allograft. This technique was also described in 2004 by Scheibell et al.10 In their series, eight patients with traumatic humeral head chondral defects were treated with osteochondral transplantation. The humeral head defect had a mean area of 150 mm 2 . At an average follow-up of 33 months, Constant scores had increased significantly in six of eight patients. With the concept of preserving humeral bone stock for potential future operative revision, the interest in shoulder humeral resurfacing has increased. The original design was developed in the 1980s with Dr. Stephen Copeland's prosthesis. This shoulder resurfacing technique is a more minimally invasive and bone-preserving option, as compared to stemmed hemiarthroplasty replacement of the proximal humerus.

RATIONALE Shoulder resurfacing or capping procedures allow the ability to perform arthroplasty with minimal change to the native anatomy. The difficulty with using stemmed humeral implants

2

is the ability to accurately and reproducibly replicate the patient's normal anatomic variability of humeral height and offset, as well as stability of the glenohumeral joint. Resurfacing of the proximal humerus allows the patient's anatomy to guide the reconstruction process and has the potential to recreate the patient's natural humeral offset and radius of curvature of the humeral head. Iannotti3 demonstrated in 1992 that the humeral articular surface is spherical in the center but the radius of curvature is approximately 2 mm less in the axial plane than in the coronal plane. The contour of the articular surface, therefore, is elliptical. Pearl7 demonstrated that retroversion of the shoulder is variable from individual to individual and even from side to side in any patient with a range from 0 to 55 degrees. Prosthetic systems that utilize a fixed angle cutting guide for humeral head resection may not reproduce the normal retroversion of a patient's humerus. The head shaft angle varies from 125 to 150 degrees, with medial offset varying from 4 to 14 mm in the coronal plane. Posterior offset of the shoulder also ranges from 2 to 10 mm. The radius of the curvature of the shoulder is slightly greater in the coronal plane than in the sagittal plane with an average range of 20 to 33 mm. Humeral height is variable but is independent of the head size. The ratio of head height to the radius of curvature varies from 3:1 to 4:1, which results in an articular surface arc of approximately 150 degrees. Pearl7 also described the detrimental effects of not recreating the normal glenohumeral anatomy at the time of arthroplasty. With an increase of the humeral head thickness by 5 mm, there is a reduction of the glenohumeral range of motion from

3

20 to 30 degrees. Decreasing the humeral head height by 5 mm also has a negative effect on the range of motion by reducing the surface arc and therefore increasing the chance of impingement at lesser angles of abduction. If the head is positioned too far superiorly, this adds an extension force vector to the rotator cuff and will disrupt the normal force couple dynamic, which also has a negative effect on shoulder range of motion as well due to inconcentric motion. Conversely, positioning the head too far inferiorly may result in abutment of the greater tuberosity on the acromion with greater ranges of abduction. In 2001, Williams14 performed a cadaveric study of the effect of humeral offset and also described similar results to those of Pearl. Inferior malposition of the humeral head, as little as 4 mm, will add to a significant increase in subacromial contact of the greater tuberosity with increased range of P.269

abduction. Humeral head malposition of 4 mm or less had a small but statistically significant effect on glenohumeral translation, and malposition of 8 mm or more in any direction resulted in significant decrease in both passive and active range of motion. Given this biomechanical information, it is imperative to restore the anatomic alignment and normal humeral length, offset, and radius of curvature to prevent a decrease in active and passive range of motion, as well as disruption of the rotator cuff and force couple mechanism. While stemmed humeral implants offer multiple humeral head sizes, radiuses of curvature, and offset, given the variability of intramedullary stem placement (angulation, height, and rotation), there are

4

potential errors in component position that may inadequately restore normal anatomic relationships. There is no osteotomy through the humeral neck or humeral head or intramedullary placement of an implant. With proximal humeral resurfacing, a majority of the bone stock of the humeral head is preserved. This allows for anatomic resurfacing of the proximal portion of the humerus and allows for later conversion to a stemmed implant, if necessary. This is an important consideration in patients who may outlast the longevity of a traditional stemmed implant through either age or activity demands and need one or possibly more revision surgeries to the shoulder. Although, the rate of humeral loosening with stemmed implants is very low.

DESIGN The current designs of proximal humeral resurfacing implants allow for fixation via bony ingrowth. The implant is typically a hemispherical cup with a concave inner surface and a centralized stem allowing placement within the anatomic center of the existing humeral head (Fig. 29.1). This design allows for placement without having to recreate the natural humeral length or humeral offset. The only variables within the designs are the radius of curvature of the implant, as well as the implant height. The current implants are influenced by the original design of the Copeland prosthesis. Levy et al.5 in 2004 demonstrated that with a Copeland resurfacing, there was minimal bone removal and good cementless fixation with a hydroxyapatite coating. Accurate placement of the guide wire is critical when performing a resurfacing. The pin alignment will determine version and inclination of the

5

prosthesis. There was no need to calculate retroversion, inclination, or offset of the humeral head since the implant was centrally placed within the existing humeral head, as dictated by an intraoperative guide wire. The advantage of the Copeland prosthesis, according to Levy, was that there was no centralized stem creating a stress riser in the midshaft of the humerus, and as such, less of a chance of periprosthetic fractures.

FIGURE 29.1 The humeral resurfacing prosthesis. Notice a wellpolished outer sphere, a concave inner surface to allow for bony ingrowth, and centralized stem.

Thomas et al.12 performed a study of the original Copeland prosthesis in 2005. They followed 39 patients for a mean of 38 months and noticed that the humeral head radius of curvature decreased by an average of 3.5%, and the offset increased by 5 mm compared to the native head. Constant scores of the patients improved from 26 to 83,

6

postoperatively. They also determined there was a nonlinear relationship between postoperative range of motion and humeral offset. Their final conclusion was that the Copeland prosthesis with its centralized peg and anatomic resurfacing restored the humeral offset and lever arm of the deltoid and supraspinatus. Currently, there are two humeral resurfacing prostheses on the market within the United States. The DePuy Global CAP (DePuy, Warsaw, Indiana) prosthesis has a porous coating with or without hydroxyapatite to allow for contact and bony ingrowth of the humeral head within its inner concave surface. There is a cruciate central stem of varying lengths to allow for central fixation within the humeral head. Variability consists of a total of 10 sizes with two head heights per diameter of curvature to allow for a total of 20 options for humeral resurfacing. The second manufacturer is the Tornier system (Tornier, Edina, Minnesota), which offers 12 sizes with three stem lengths that has a central trephine for fixation of the stem. The inner surface of the hemispherical cup is plasma sprayed with a hydroxyapatite coating for bony ingrowth.

MODE OF FAILURE The methods of failure of proximal humeral resurfacing implants are similar to many other types of resurfacing arthroplasties and include infection, dislocation, iatrogenic fracture, periprosthetic humeral head fracture, and component loosening. One main risk of failure includes dislocation or subluxation of the humerus within the glenohumeral joint. Care must be taken during the approach to maintain the force couple relationship of the rotator cuff, as well as the continuity of the subscapularis muscle. If a deltopectoral

7

approach is performed, a weak or faulty repair of the subscapularis muscle can lead to anterior subluxation or gross dislocation and instability of the humerus in the postoperative course. With this approach, a strong repair of the tendon is an absolute necessity, and the surgeon should check the “safe zone” of his or her repair. After suturing, under direct visualization, the shoulder should be brought into external rotation and the angle the arm can achieve without undue tension on the repair is noted. Fracture of the humerus is also a risk. Iatrogenic fracture can be diminished with careful surgical technique. Iatrogenic fracture can occur during original dislocation of the humeral head for preparation of the implant. Excessive force should not be used to dislocate the shoulder anteriorly. If difficulty is encountered, more extensive anterior capsular releases should be performed to allow easy dislocation of the shoulder to prevent this potential injury. Another common time for fracture occurs during reaming of the humeral head, if the reamer becomes engaged on bone and then torque is applied to the humeral surface. This complication can be reduced by starting the bony reamer for the humeral head with no contact on P.270

the humeral surface. Once the reamer is in full revolution, the reamer can gradually be lowered for gradual circumferential reaming of the humeral head. Periprosthetic fracture, while a potential complication, occurs less than with a stemmed humeral arthroplasty. Given the fact that the stem is within the humeral head and does not extend within the medullary canal, the medial calcar of the shoulder

8

is preserved allowing better force transmission. The prosthesis disperses force in a load sharing pattern within the humeral head, which is then transmitted to the normal trabecular lines of the humeral neck and into the proximal portion of the humeral shaft. With this design, there is no large metal stem within the canal that disperses force to alternative areas of bone. Also, within the shaft, there is no central stem and therefore, no stress riser in the intramedullary canal, reducing the risk of fracture as well. Component loosening is the last main mechanism of failure and can be minimized with a well-fitting centralized stem as well as a circumferentially reamed humerus that fits the undersurface of the component adequately. Once the component is well seated within the proximal portion of the humeral head, this allows bony ingrowth within the undersurface of the concave prosthesis. The risk of loosening increases when there is less contact with good bone on the undersurface of the prosthesis. We recommend a minimal of 70% to 75% good bone in contact with the prosthesis at final implantation.

9

FIGURE 29.2 Preoperative AP external rotation (A), internal rotation (B), and axillary views (C) of a patient with complete articular cartilage loss due to previous trauma. She underwent humeral resurfacing and is now pain free and back to normal activities. Postoperative internal rotation (D), external rotation (E), and axillary (F) are shown.

INDICATIONS Proximal humeral resurfacing arthroplasty is indicated for a variety of conditions. This implant should be considered more frequently in the younger, more active patient with humeral pathology (Fig. 29.2). With these types of patients, there is a greater desire to preserve bone stock to allow for easier future 10

P.271

conversion to either a hemiarthroplasty or total shoulder arthroplasty, if required in the future. However, care must be taken when approaching a proximal humeral resurfacing when the glenoid articular surface has wear. While it is possible to resurface the glenoid with either a polyethylene implant or a biologic soft tissue interposition, the humeral head is not removed as it is in the preparation for a total shoulder arthroplasty or hemiarthroplasty. With the humeral head still attached to the shaft, it is significantly more difficult to expose the glenoid, obtain complete visualization, and perform adequate preparation and implantation of a glenoid component.

FIGURE 29.2 (Continued).

11

Avascular necrosis is a potential indication for proximal humeral resurfacing; however, vascular studies or magnetic resonance imaging may be considered prior to implantation of the proximal humeral component. The component must be supported by an adequate amount of subchondral bone on the humeral head. Significant and extensive avascular necrosis that has compromised the subchondral bone must be approached with caution. Continued extension of the necrotic area may compromise the underlying support and lead to component loosening or subsidence. Arthritic conditions or isolated osteochondral defects are other potential indications for implantation. With conditions such as rheumatoid arthritis or osteoarthritis, minimal bony deformity and glenoid involvement should be verified as mentioned above. Specifically for rheumatoid and other inflammatory classes of arthritis, the surgeon must understand that implantation of the humeral resurfacing arthroplasty, while it can provide improved function and improved pain relief, will likely be a temporary solution. These disease processes are synovial in origin and will likely affect the glenoid articular cartilage in the future, requiring a potential conversion to total shoulder arthroplasty in the future. Joint incongruity is not a contraindication as long as the joint incongruity exists mainly on the humerus with little change to the glenoid surface. The joint incongruity must be surface level without significant incongruity within the subchondral bone of the humeral head, given the fact that again this subchondral bone must be present for good support of the component. Cuff tear arthropathy is a relative indication. Traditionally, implantation of a larger headed, stemmed humeral component

12

in valgus has yielded good results in the past. This component and positioning allowed articulation with the acromion and glenoid and also increased the offset of the humerus, thereby increasing the moment arm of the deltoid for improved shoulder abduction. The same technique can be employed with implantation of a larger humeral resurfacing component. This component can be placed in a slightly more vertical position that is dictated by the anatomy of the patient (Fig. 29.3). Once reduced, the proximal humeral surface is then given a dual articulation with both the acromion and the glenoid.4 , 13 Stiffness, loss of function, and pain refractory to conservative management due to other underlying diseases are also indications for implantation of this device. However, care P.272

must be taken at this point to rule out other metabolic diseases or neurologic causes of pain since implantation of a proximal humeral resurfacing device will not relieve pain associated with neurologic pathology.

13

FIGURE 29.3 Preoperative (A) and postoperative AP (B) and axillary (C) views in a 71-year-old farmer with rotator cuff arthropathy. Postoperatively, he is active, has decreased pain, is satisfied, and has an 80-degree arc of forward elevation and abduction.

14

FIGURE 29.3 (Continued).

CONTRAINDICATIONS An absolute contraindication to the implantation of a proximal humeral resurfacing implant is a current active infection within the glenohumeral joint. Previous history of infection within the glenohumeral joint should also be approached with caution. If implantation of a proximal humeral component in a previously infected joint is going to proceed, care must be taken to diligently verify the resolution of the infection within the shoulder joint. The authors recommend serial complete blood counts (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels. Also, aspiration of the joint after sterile preparation of the shoulder with negative culture results and an intraarticular cell count of less than 1500 leukocytes is recommended.

15

Adequate bone stock is important to the stability and ingrowth of the device. As mentioned previously, pathologic subchondral bone that does not support at least 70% to 75% of the undersurface area of the component would be a relative contraindication to implantation of this device. Moderate-to-severe glenoid cartilage loss or significant glenoid bone loss is also a relatively contraindication to implantation of this device. While glenoid resurfacing with either biologic interposition or polyethylene implantation is possible, the ability to resurface the glenoid is technically more demanding with the presence of the humeral head. In these patients, total shoulder arthroplasty is a better implant choice. Sperling et al.11 stated in 1998 that in patients with arthritic involvement of both sides of the glenohumeral joint, total shoulder arthroplasty yields better results than hemiarthroplasty. In his series of 18 patients who underwent glenoid replacement after humeral hemiarthroplasty, seven patients had unsatisfactory results. The revision to total shoulder arthroplasty gave inferior outcomes compared to primary total shoulder arthroplasty in his series. This outcome was also reported by Rispoli et al.9 in 2006. In that series, 51 patients with hemiarthroplasty for glenohumeral osteoarthritis, with a mean age of 59 years, were followed for 11 years on average. Of his 51 patients, 10 had excellent results, 20 had satisfactory results, and 21 had unsatisfactory results, as reported with the modified Neer criteria. Of these 51 patients, 10 (19.6%) underwent revision for painful glenoid arthrosis. While there currently is no published prospective randomized study comparing proximal humeral resurfacing implant to total shoulder arthroplasty, there are many articles comparing

16

hemiarthroplasty to shoulder arthroplasty, and examination of this data may shed light on the performance of a resurfacing humeral design. In a patient with preexisting moderate-tosevere glenoid arthrosis, the choice of a total shoulder arthroplasty is superior to proximal humeral resurfacing. However, in a patient with minimal glenoid disease, a proximal humeral resurfacing implant can be performed and provide good pain relief and return of function.

PREOPERATIVE PLANNING A careful history and physical examination must be performed on any patient before undergoing a surgery with proximal humeral resurfacing. The history must include the type of pain that the patient may experience. It is important to note whether the pain is typical of that of arthritic pain or a pain that may be related to a type of neurologic condition. Other important historical factors include any patient-related limitations of motion, night pain, constitutional symptoms, or rotator cuff symptomatology. A detailed history of avascular necrosis within either the shoulder or any other body part should also be elicited. Other comorbidities, such as diabetes, coronary artery disease, atherosclerosis, or obesity, should be documented, as they may increase either the potential risk of infection, risk of morbidity or mortality to the patient, postoperative complication rate, or the difficulty of the case. The physical examination should be typical of that of any patient with shoulder pathology. It is mandatory in any patient with shoulder pain that cervical spine pathology be ruled out prior to intervention. Range of motion, both passive and active, should be documented. The patient's rotator cuff

17

should also be evaluated in terms of both pain and weakness to the supraspinatus, infraspinatus, and subscapularis muscles. The deltoid muscle must also be checked preoperatively, and P.273

the function of both the axillary and musculocutaneous nerves should be well documented prior to any surgery since these are potential nerves at risk. Typical imaging studies to be obtained in the preoperative setting include standard AP, lateral, and axillary radiographs of the shoulder. If there is any questionable glenoid pathology or loss of bone stock about the glenoid, a CT scan with coronal and sagittal reconstruction should be obtained. The decision to obtain an MRI of the shoulder to evaluate the rotator cuff should be based upon history and physical examination findings. If it was noted during the patient's history that rapid destruction of the humeral head occurred, other pathologic processes such as a syrinx of the cervical spine must be considered and potentially evaluated with the preoperative MRI of the cervical spine. The authors recommend preoperative templating prior to operative intervention. While the size of the implant at the time of surgery may not exactly match the templated size, it gives the surgeon an additional indicator of a potential error if the implanted size is vastly different from the templated size. It is important to remember to adjust the templated size due to radiographic magnification or utilize digital templating systems if electronic radiographs were obtained.

TECHNICAL CONSIDERATIONS

18

One of the first considerations when planning a proximal humeral resurfacing is the surgical approach. The standard approach is considered through the deltopectoral interval, which is usually the most familiar to surgeons. The interval is developed between the deltoid and the pectoralis major after immobilization of the cephalic vein. Depending on the body habitus of the patient, as well as the difficulty to dislocate the shoulder, it may be necessary to take down a portion of the upper insertion of the pectoralis major tendon. The next step is to identify the clavipectoral fascia and to incise lateral to the conjoined tendon. Following this, the subscapularis tendon is identified and anterior humeral circumflex vasculature ligated. The subscapularis is released with care taken to leave a small portion of the tendonis insertion in order to facilitate a strong repair at the completion of the operation. This repair is extremely important since the subscapularis is the primary restraint to anterior dislocation or subluxation of the humerus. An alternative is the superior approach, through the anterior deltoid raphae. This approach is useful for treatment of cuff tear arthropathy when the supraspinatus is absent. The incision extends from the acromioclavicular joint along the anterior border of the acromion to approximately 4 cm distal to the edge of the acromion. The deltoid is then split along the anterior and middle raphae. Care is taken not to extend the split more than 5 cm distally to the edge of the acromion due to potential injury to the axillary nerve. We recommend placing a stay stitch at the level of the deltoid, 3 to 4 cm distal to the lateral edge of the acromion to prevent any inadvertent dissection past this point. Once the deltoid is incised, the rotator interval is then split to allow for direct

19

exposure to the superior aspect of the humeral head. This approach leaves the subscapularis tendon intact, which helps prevent the potential complication of anterior instability of the shoulder. Following selection of the humeral head size, a guide wire is placed within the center of the humeral head to allow for reaming. As the reamer is brought down over the guide wire, the reamer should be started prior to engaging the humeral head to prevent iatrogenic fracture. The insertions of the rotator cuff are very close to the site of reaming, and care must be taken not to violate their fibers (Fig. 29.4).

FIGURE 29.4 The guide wire is inserted in the central portion of the humeral head, dictated by the patient's anatomy. The humeral head has been reamed in preparation for the implant.

20

FIGURE 29.5 The final prosthesis is implanted on the humerus.

Following reaming, the insertion site for the stem is prepared in the proximal aspect of the humeral head according to the manufacturer's directions. A trial prosthesis is evaluated for correct positioning, range of motion, and stability of the shoulder. There should be a minimum of 30 degrees of external rotation, and with the arm held in slight abduction (approximately 20 degrees), one should be able to sublux the humeral head posteriorly approximately 50% (Fig. 29.5).

RESULTS Levy and Copeland5 in 2004 published their series of 79 patients, comparing 37 proximal humeral resurfacing arthroplasties to 42 total shoulder arthroplasties. The mean age of the patients was 73, with an average follow-up of 7.6 years. The constant scores of the total shoulder arthroplasty group were 94% as compared to the proximal humeral 21

resurfacing group of 91%. There were four revisions in the total shoulder arthroplasty group with no revisions within the resurfacing group. Levy and Copeland concluded that outcomes in patients who underwent proximal humeral resurfacing are comparable to total shoulder arthroplasty. Levy6 published another series in 2004 also comparing proximal humeral resurfacing patients with total shoulder P.274

arthroplasty patients. In this series, there were 33 proximal humeral replacements with the Copeland prosthesis and 42 total shoulder arthroplasties. The average follow-up was 6.5 years. The adjusted constant score was 71 in the proximal humeral resurfacing compared to 76 in the total shoulder arthroplasty group. There were two patients who required revision in the total shoulder arthroplasty group and one patient who required a revision to a total shoulder arthroplasty in the humeral resurfacing group. His conclusions showed that proximal humeral resurfacing yielded comparable results to total shoulder arthroplasty. Raiss8 reported in 2007 his series of 10 patients with fixed anterior glenohumeral dislocation with humeral bone loss. In his series, all patients were treated with the Copeland humeral resurface arthroplasty. The follow-up averaged of 24 months. In this complex series of patients, there was one redislocation and one case of glenoid erosion. They noted at final follow-up that the humeral head was centered in 9 out of 10 cases and the patients were satisfied with an increased Constant score from 23 preoperatively to 61 at follow-up. There were no signs of radiographic loosening of the prosthesis in any of the patients within this series.

22

Jerosch et al.4 reported on their series in 2008 evaluating the Copeland prosthesis in patients with rotator cuff arthropathy and intact subscapularis function. In their series, there were 25 patients with a mean age of 69, followed for an average of 26 months postoperatively. Constant scores increased with these patients from 14 preoperatively to 53 postoperatively. There was an 88% patient subjective satisfaction rate. They noted no complications during their follow-up interval. Bailie1 reported his series in 2008, which consisted of 36 patients less than 55 years of age. In his series, patients were treated with proximal humeral resurfacing with the Copeland prosthesis and either microfracture or biologic resurfacing of the glenoid with Graftjacket (Wright Medical Technology, Arlington, Tennessee) interposition. The mean follow-up was 38.1 months, with a minimum of 2 years. A visual analog pain score improved from 7.5 preoperatively to 1.5 postoperatively. The ASES score improved from 29.87 preoperatively to 87.7 postoperatively. At final follow-up, there was no radiographic evidence of loosening of the prosthesis, and only one patient out of 36 was converted to total shoulder arthroplasty for pain. The complications include one subscapularis rupture at 6 weeks, three patients with arthrofibrosis, and one patient with postoperative hematoma.

CONCLUSIONS Proximal humeral resurfacing arthroplasty of the shoulder is a good surgical option for patients with humeral head pathology and minimal glenoid involvement. The results of proximal humeral replacement are comparable to those of shoulder arthroplasty in patients without substantial glenoid pathology. The ability to convert to a future stemmed implant of the

23

humerus is theoretically easier considering the preservation of bone stock and the lack of previous fixation within the intramedullary humeral canal. Humeral resurfacing can be used in younger patients, isolated humeral arthritis, rotator cuff arthropathy, or patients with avascular necrosis of the humerus. However, one should be aware of the potential limitations of this procedure including difficulty of glenoid exposure with the humeral head being intact, inability to use an eccentric humeral head, and minimal options to increase humeral offset.

References 1. Bailie DS, Llinas PJ, Ellenbecker TS: Cementless humeral resurfacing arthroplasty in active patients less than fifty-five years of age. J Bone Joint Surg Am 90:110-117, 2008. 2. Gerber C, Lambert SM: Allograft reconstruction of segmental defects of the humeral head for the treatment of chronic locked posterior dislocation of the shoulder. J Bone Joint Surg Am 78:376-382, 1996. 3. Iannotti JP, Gabriel JP, Schneck SL, et al: The normal glenohumeral relationships. An anatomical study of one hundred and forty shoulders. J Bone Joint Surg Am 74:491500, 1992. 4. Jerosch J, Schunck J, Morsy MG: Shoulder resurfacing in patients with rotator cuff arthropathy and remaining subscapularis function. Z Orthop Unfall 146:206-210, 2008. 5. Levy O, Copeland SA: Cementless surface replacement arthroplasty (Copeland CSRA) for osteoarthritis of the shoulder. J Shoulder Elbow Surg 13:266-271, 2004.

24

6. Levy O, Funk L, Sforza G, Copeland SA: Copeland surface replacement arthroplasty of the shoulder in rheumatoid arthritis. J Bone Joint Surg Am 86-A:512-518, 2004. 7. Pearl ML: Proximal humeral anatomy in shoulder arthroplasty: Implications for prosthetic design and surgical technique. J Shoulder Elbow Surg 14:99S-104S, 2005. 8. Raiss P, Aldinger PR, Kasten P, et al: Humeral head resurfacing for fixed anterior glenohumeral dislocation. Int Orthop 33(2):451-456, 2009. 9. Rispoli DM, Sperling JW, Athwal GS, et al: Humeral head replacement for the treatment of osteoarthritis. J Bone Joint Surg Am 88:2637-2644, 2006. 10. Scheibel M, Bartl C, Magosch P, et al: Osteochondral autologous transplantation for the treatment of full-thickness articular cartilage defects of the shoulder. J Bone Joint Surg Br 86:991-997, 2004. 11. Sperling JW, Cofield RH, Rowland CM: Neer hemiarthroplasty and Neer total shoulder arthroplasty in patients fifty years old or less. Long-term results. J Bone Joint Surg Am 80:464-473, 1998. 12. Thomas SR, Sforza G, Levy O, Copeland SA: Geometrical analysis of Copeland surface replacement shoulder arthroplasty in relation to normal anatomy. J Shoulder Elbow Surg 14:186-192, 2005. 13. Werner A, Hedtmann A: Surface replacement shoulder: Arthroplasty indications and limits. Orthopade 36:996-1001, 2007. 14. Williams GR Jr, Wong KL, Pepe MD, et al: The effect of articular malposition after total shoulder arthroplasty on glenohumeral translations, range of motion, and subacromial impingement. J Shoulder Elbow Surg 10:399-409, 2001.

25

26

Chapter 30 Reverse Total Shoulder Arthroplasty Joaquin Sanchez-Sotelo Reverse total shoulder arthroplasty designs represent one of the major advances introduced in the field of reconstructive shoulder surgery over the last two decades. Reverse shoulder arthroplasty designs combine a convex hemispherical glenoid component and a humeral stem with a concave proximal end. The first reverse shoulder arthroplasty design was introduced more than 20 years ago in Europe for the reconstruction of shoulders with end-stage cuff-tear arthropathy.16 The initial design was refined over time, and several modern reverse prostheses are now available and have been used over the last 5 to 10 years, with promising results for patients with cuff-tear arthropathy. However, as the indications have been expanded from pure cuff-tear arthropathy to revision surgery for complex reconstructive problems, a substantial rate of complications and less successful outcomes have been reported, especially with longer follow-up.41 The reverse prosthesis is extremely attractive for multiple reasons. It provides impressive early functional improvements in patients with very common problems for which there is really no other good solution.4 , 9 , 41 By replacing both sides of the joint, it offers more reliable pain relief as compared to hemiarthroplasty.33 It restores active elevation, improves stability, and may allow a simpler, faster recovery. However, there are some important concerns with the reverse prosthesis. The mechanical failure rate of reverse arthroplasty may end up being high, similar to other

1

previously used constrained designs. In addition, when complications happen, they may be catastrophic. Revising a failed reverse arthroplasty represents a technical challenge. Finally, as with other new technologies, it may be subject to overuse currently. The purpose of this chapter is to review the rationale and design principles of the reverse prostheses, their current indications, and provide a brief review of published outcomes.

REVERSE DESIGN RATIONALE The combination of an arthritic joint and a massive rotator cuff tear is usually associated with moderate to severe pain and very limited active motion and strength (Fig. 30.1). The lack of a functional rotator cuff allows superior migration of the humeral head, with loss of a stable fulcrum. Failed rotator cuff surgery with violation of the coracoacromial arch further facilitates anterosuperior escape of the humeral head, which compromises shoulder function. In the absence of a stable fulcrum, contraction of the deltoid fails to elevate the arm, as the humeral head is translated superiorly instead of rotating on the surface of the glenoid. Use of an anatomic total shoulder arthroplasty in the absence of a functional cuff is believed to be associated with a high rate of glenoid component failure secondary to edgeloading of the humeral head on the anterosuperior rim of the glenoid component.13 Anatomic hemiarthroplasty has been the surgical procedure of choice for patients with cuff-tear arthropathy for many years (see chapter on cuff-tear arthropathy), but functional gains are very limited and a substantial number of patients continue to experience pain

2

probably due to a combination of abnormal mechanics and a nonresurfaced glenoid.33 Dr. Paul Grammont, a French orthopaedic surgeon, developed the first successful reverse prosthesis in 1991, as a modification of his own previous design, introduced in 1985.16 The goals of his design, the Delta III reverse prosthesis (DePuy, Warsaw, Indiana), were (a) to use a semiconstrained ball-and-socket implant to improve stability and compensate for an absent rotator cuff and (b) to decrease the risk of mechanical failure of the glenoid component by medializing the center of rotation of the joint and using divergent screws for fixation of an uncemented glenoid component. The name “Delta” emphasized the fact that the deltoid would be responsible for most of the function after replacement (Fig. 30.2).

3

FIGURE 30.1 Right anteroposterior radiograph of a patient with cuff-tear arthropathy with advance arthritis and proximal migration of the humeral head secondary to massive cuff deficiency.

P.276

4

FIGURE 30.2 Anteroposterior radiograph shows the Delta III reverse prosthesis with a convex cementless glenoid component fixed with screws and a cemented concave humeral component. Note the large distance between the acromion and proximal humerus, reflecting the distal translation of the center of rotation and consequent increased deltoid tensioning.

Improved Function Functional improvements after reverse prosthesis in patients with massive cuff deficiencies are largely due to the semiconstrained nature of the implant and increased deltoid tensioning. In the normal shoulder, an intact rotator cuff 5

compresses the humeral head against the glenoid and keeps it centered and stable to optimize active motion. In the absence of a functional rotator cuff, a ball-and-socket type of joint will maintain enough stability to allow functional active motion using mostly the deltoid. Gutierrez et al. have analyzed the relative effect of different parameters in improving range of motion before impingement. Increased offset seems to have the greatest effect, followed by inferior position of the glenoid component. Glenosphere tilt, humeral neck-shaft angle, and glenosphere size play a definite but lesser role.18 Reverse prostheses also displace the center of rotation distally compared to both the normal and arthritic shoulders. The resultant increased tensioning and mechanical advantage of the deltoid translate in a more powerful deltoid function. Finite element analysis studies have shown the increased mechanical advantage of the deltoid in reverse arthroplasty, as compared to anatomic designs.38 The ideal soft tissue tension after reverse arthroplasty is not well understood: excessive soft tissue tension may result in brachial plexus or axillary nerve irritation, acromial stress fractures, or a difficult reduction with increased risk of intraoperative humeral periprosthetic fractures. On the other hand, insufficient soft tissue tension may be associated with decreased function and increased risk of dislocation.

Decreased Mechanical Failure Early constrained designs were associated with a relatively high mechanical failure rate. Two important design features were introduced with the Delta III reverse prosthesis in order to provide longer lasting fixation. First, the glenoid component

6

is approximately a third of a sphere. Thus, the center of rotation is medial to the component-bone interface, which is subjected to compressive forces instead of shearing forces.3 Secondly, the component is coated with hydroxyapatite and fixed with peripheral divergent screws, which increases the glenoid pull-out strength. Two of the screws also lock into the baseplate. Initial fixation has been shown to be affected by bone density as well as by the purchase of each individual screw.7 The main disadvantage of a medial center of rotation is the contact, which occurs in adduction between the medial aspect of the proximal humerus and humeral component and the inferior aspect of the glenoid. This repetitive contact leads to bone loss under the inferior aspect of the glenoid component, which is described on radiographs as notching.26 The longterm consequences of glenoid notching are not fully understood. The potential for accelerated polyethylene wear and progressive bone loss is worrisome.26 In order to decrease the frequency of notching, it is now recommended to place the glenoid component as low as possible on the native glenoid surface,21 , 23 , 26 , 30 , 43 and some designs have glenospheres with an inferior offset. One additional potential disadvantage of a medial center of rotation may be insufficient tensioning of the posterior external rotators, which may translate into less active motion and more weakness in external rotation. A different design of glenoid component with a lateral center of rotation (RPS, Encore) has been introduced to prevent notching (Fig. 30.3). By placing the center of rotation more lateral, contact is avoided between the humeral component and the glenoid. The offset of the center of rotation seems to

7

have a beneficial effect on range of motion.21 However, at least theoretically, a lateral offset may lead to increased shearing P.277

forces and loosening.40 There are no comparative clinical studies between implants with a medial and a lateral center of rotation. In addition, the fixation of the Encore RPS glenoid component is improved by using a central screw instead of a post, which provides compression and four peripheral locking screws. This strong fixation may compensate for the increased stress at the bone-implant interface secondary to the lateralized center of rotation.22

8

FIGURE 30.3 Right anteroposterior radiograph of an Encore reverse prosthesis, designed with a lateral center of rotation.

Improvements in component design continue to be introduced, and the new Delta Xtend design (DePuy) has a different locking-screw mechanism, which allows to angle the screws in different positions, provide compression before locking the screws to the baseplate, and also to use all four peripheral screws in the locking mode. There are several other available systems that provide small changes compared to the design of the implants described.

INDICATIONS 9

Cuff-tear arthropathy is the main and probably the ideal indication for a reverse prosthesis as patients with cuff-tear arthropathy seem to achieve the best outcome after reverse shoulder arthroplasty.4 , 41 It was initially recommended only for older patients with decreased functional demands and preoperative active elevation under 90 degrees. As surgeons have gained more experience with the reverse prosthesis, younger patients as well as those with overhead active elevation but moderate to severe pain are being offered a reverse prosthesis instead of a hemiarthroplasty, despite the lack of information about the long-term results in younger patients. TABLE 30.1 INDICATIONS FOR REVERSE PROSTHESES

• Cuff-tear arthropathy

• Massive rotator cuff tear with pseudoparalysis

• Severe inflammatory arthritis with a massive cuff tear

• Failed shoulder arthroplasty

•

Absence of tuberosities (failed hemiarthroplasty for fracture/nonunion)

•

Absence of cuff (failed hemiarthroplasty for cuff-tear arthropathy)

•

Instability

10

• Proximal humerus fractures

• Proximal humerus nonunions

• Reimplantation for deep periprosthetic infection

• Reconstruction after tumor removal

TABLE 30.2 ADVANTAGES AND DISADVANTAGES OF THE DELTOPECTORAL AND SUPERIOR APPROACHES

Deltopectoral

Advantages

Disadvantages

•

Familiarity

•

Subscapularis detachment

•

Better access for inferior capsular release

•

Glenoid exposure may be difficult in some patients

11

Superior

•

May be easily extended distally for difficult revisions or intraoperative fracture fixation

•

May be easily extended to anteromedial approach

•

Easier glenoid exposure

•

More difficult to extend should complications arise

•

Avoids subscapularis detachment (↓ dislocation rate?)

•

Risk of axillary nerve damage with accidental distal extension of the split

•

Limited access to the inferior capsule for

Other indications are still somewhat controversial (Table 30.1). Reverse arthroplasty is very attractive for patients with a massive rotator cuff tear and pseudoparalysis even in the absence of arthritis and severe pain,43 but this represents a 12

departure from traditional thinking when prosthesis were only considered to replace damaged joint surfaces. Rheumatoid patients will present sometimes with end-stage arthritis and absent cuff tissue,32 but they tend to have substantial osteopenia, which may compromise glenoid fixation or weaken the subacromial arch and facilitate acromial fractures. Revision of a failed anatomic shoulder arthroplasty has emerged as a very attractive indication if the tuberosities and the cuff are compromised as well as in patients with prosthetic instability.4 , 27 , 28 , 41 The reverse shoulder arthroplasty is also being explored for the treatment of acute proximal humerus fractures,25 , 42 proximal humerus nonunions,29 and reconstruction after tumor surgery. Reimplantation after removal of an infected shoulder arthroplasty is also attractive10 as many of these patients will have a compromised, scarred cuff after the infection and multiple surgeries.10

SURGICAL TECHNIQUE Surgical Exposure Reverse prostheses may be implanted through a deltopectoral approach or a superior transdeltoid approach (Table 30.2). A transacromial approach, as recommended initially by Dr. Grammont, is not favored currently because of the associated risk of acromion nonunion and secondary deltoid dysfunction.

Deltopectoral Approach The deltopectoral approach is very well known to all shoulder surgeons. Our preference is to identify the interval proximally and develop it from proximal to distal, mobilizing the cephalic vein medially after coagulation of its multiple deltoid tributaries. In some patients with cuff-tear arthropathy, the 13

subscapularis is partly present.33 Our preference is to divide the subscapularis tendon, leaving approximately 1 cm of lateral tendon stump. The vessels at the inferior border of the subscapularis are coagulated, and the inferior capsule may then be released subperiosteally. P.278

Superior Transdeltoid Approach This exposure was popularized in Europe in order to access the shoulder joint from above through the deficient cuff without detaching any remaining subscapularis and anterior capsular structures.3 , 37 It may provide an easier access to the glenoid. This approach basically involves elevating the anterior deltoid off the anterior acromion and splitting the muscle fibers distally for no more than 5 cm to avoid injury to the axillary nerve. The main disadvantages of this approach include more limited access to the inferior capsule for release, difficulty extending the approach distally if humeral complications arise or in the revision setting, and potential for injury to the axillary nerve with inadvertent extension of the deltoid split distally.

Soft Tissue Releases Soft tissues releases are needed in order to obtain motion and balanced stability. Most shoulder conditions are associated with decreased passive elevation secondary to contracture of the inferior capsule; subperiosteal capsular release off the humerus is safe and helps restore full elevation. Anterior or posterior capsular releases may be

14

needed, depending on the underlying pathology to improve motions in all planes if possible.

Humeral Osteotomy The humeral osteotomy angle varies slightly depending on the design used, but most designs require an osteotomy with a head-shaft angle of approximately 50 to 55 degrees (Fig. 30.4).3 This steeper osteotomy angle facilitates glenoid exposure and decreases glenohumeral impingement in adduction21 but results in more bone removal compared to anatomic arthroplasties.

15

FIGURE 30.4 An example of a cutting guide used for the proximal humerus osteotomy. Note the version rod, aligned in this case in 30 degrees of retroversion.

There is some controversy regarding the ideal retroversion of the humeral component. Most European surgeons favor a nonanatomic retroversion of approximately 0 to 10 degrees, which may provide more anterior stability but may result on more limited external rotation before impingement.3 The traditional 30 degrees of retroversion recommended for most anatomic arthroplasties is favored by American surgeons for the reverse prosthesis as well, potentially providing more external rotation and an easier conversion between anatomic and reverse implants.9 In addition, implantation of a press-fit stem requires approximately 30 degrees of retroversion to obtain ideal fit.

Glenoid Preparation and Implantation The goals of glenoid implantation are to achieve intimate contact between the uncemented base-plate and the native glenoid to promote ingrowth, obtain secure screw fixation of the component, and position the component to decrease the potential for glenohumeral impingement and notching. Adequate exposure of the glenoid is critical and cannot be overemphasized. The risk of notching is decreased by placing the glenoid component inferiorly and maybe with a slight inferior inclination or tilt (Fig. 30.5). Inferior glenoid tilt may also be related to decreased stress on the implant-bone interface.19 Some designs offer an offset glenosphere to position the center of rotation slightly inferiorly even if the baseplate needs to be implanted in a more centered position to use the best bone stock. Some anatomic studies of the scapula 16

suggest the development of smaller concave baseplates aligned with the two inferior quadrants of the glenoid, use of a 42-mm eccentric glenosphere, and partial removal of the infraglenoid tubercle if intraoperative impingement is detected.30 Current designs use screws locked to the baseplate in one or more positions. Most components have five fixation screws P.279

or a central post and four fixation screws. Newer designs allow screw compression before locking. The best available bone for screw fixation of the glenoid component seems to be at the base of the coracoid, the spine of the scapula, and the so-called scapular pillar.23 Using screws into the spine of the scapula and anteriorly below the central peg decreases baseplate micromotion even in the presence of a central cavitary defect.8 For specific components such as the Aequalis reverse, the ideal location of the central post has been determined to be 12 mm proximal to the inferior edge of the glenoid.24

17

FIGURE 30.5 The baseplate is implanted relatively low, flush with the inferior edge of the glenoid and typically fixed with a combination of locking and nonlocking screws, depending on the implant used.

The size of the glenosphere implanted influences both motion and stability.21 A larger glenosphere diameter is associated with more motion before impingement, potentially providing more active motion and less risk of dislocation. However, other factors such as greater offset and inferior glenoid placement have a more profound effect on range of motion.21

Humeral Preparation and Implantation

18

Most available reverse humeral components are designed for fixation with bone cement. The canal is reamed and/or broached leaving some cancellous bone for cement interdigitation. There is very limited data to guide the ideal height for humeral component implantation. Trial components with different polyethylene thicknesses may be tested for stability and motion in order to determine the ideal height and soft tissue tension. As a general rule, the reduction and dislocation maneuvers should require some effort; the conjoined tendon should be felt to be under some tension; there should be minimal separation between the humeral and the glenoid components in full adduction; and a functional range of passive motion without dislocation should be achieved. Adequate soft tissue tension is paramount for stability as stability seems to depend much more on the compressive forces generated by muscles than on the socket depth or the glenosphere size.20 To reproduce the soft tissue tension achieved with the trials, the real humeral component is then cemented in the selected height and version with standard cementing techniques (Fig. 30.6).

19

FIGURE 30.6 Humeral component being cemented into place.

Proximal humeral bone support is probably required for most reverse humeral components. In the absence of proximal humerus bone stock, these smooth cemented components will be subjected to excessive torsional stresses, which may lead to loosening. In fact, the earlier generation of modular reverse humeral components became disassembled in some patients with no proximal humeral bone. Consideration should be given to allograft augmentation of the proximal humerus in patients with severe bone loss (Fig. 30.7).

20

Cementless fixation of the humeral component is very attractive in shoulder arthroplasty. Aseptic loosening of cemented P.280

humeral components is very rare, even with old cementing techniques.34 When revision of a well-fixed cemented humeral component is required for other reasons (infection, instability, etc.), removal of cement from the humeral canal is challenging and may lead to intraoperative fractures. Cementless components designed for proximal fixation may be easier to revise, and this has led to interest in cementless humeral components for reverse prosthesis. Currently, there is very limited information about the outcome of these components.

21

FIGURE 30.7 A: Left anteroposterior radiograph showing a failed tumor prosthesis

22

with instability and proximal humerus bone loss. B: Reconstruction with a reverse prosthesis and a structural allograft. C: Postoperative anteroposterior radiograph showing the final reconstruction.

FIGURE 30.7 (Continued).

Closure, Tendon Transfers, and Postoperative Treatment In many instances, when a reverse prosthesis is implanted, the rotator cuff is completely deficient and closure is limited to the deltopectoral interval or the deltoid split, depending on

23

the approach. However, when the operation is performed through a deltopectoral approach, repair of any remaining subscapularis seems to be associated with a lower risk of dislocation. A high rate of postoperative hematomas has been reported by some authors; attention should be paid to avoidance of large empty spaces during closure. As mentioned below, gains in external rotation are uncommon after reverse shoulder arthroplasty, especially when there is fatty infiltration of the teres minor.36 In the absence of a functional teres minor, some authors have proposed combining implantation of a reverse implant with transfer of the latissimus dorsi around the humeral shaft through the same deltopectoral approach.1 Biomechanical studies suggest that latissimus dorsi transfer does improve external rotation torque when combined with a reverse prosthesis and also that an insertion site on the posterior aspect of the greater tuberosity close to the teres minor insertion produces a greater moment arm.11 This associated procedure may lead to better final external rotation, which seems to be associated with higher patient satisfaction.2 , 15 The postoperative management is largely based on surgeon preference. Some surgeons feel that limited postoperative protection is needed and will let patients use their arm actively 2 to 3 weeks after surgery. Other surgeons favor no or passive motion for the first 6 weeks and protected use of the upper extremity for up to 3 to 6 months.6

OUTCOME The first large outcome study reporting the results of Dr. Grammont's reverse prosthesis was published by Sirveaux et al.37 in 2004. These authors reported on 80 patients with a

24

mean follow-up of 3.6 years. The procedure was associated with good pain relief in 96% of the patients, mean active elevation increased from 73 to 138 degrees, and Constant scores (which combine pain, motion, and activity, with a possible maximum score of 100 points) improved from 22 to 65 points (Fig. 30.8). There were five cases of aseptic loosening and seven of glenoid dissociation, and three implants were revised. The integrity of teres minor was found to be essential for recovery of external rotation and was associated with better Constant scores.

FIGURE 30.8 Reverse arthroplasty provides good pain relief and functional results in patients with cuff-tear arthropathy. A: Postoperative anteroposterior radiograph. B: Active elevation.

P.281

25

Slightly, worse results were reported by Werner et al.43 also using the Delta III implant. These authors reported on 58 consecutive shoulders, followed for 3 years. Relative Constant scores (corrected for age and gender) improved from 29% to 64% and active elevation improved from 42 to 100 degrees, but there was an overall complication rate of 50% and an overall reoperation rate of 33%. Results were noted to be worse in the revision setting. The longest follow-up study to date was reported by Guery et al.17 These authors reported on 80 prostheses implanted mostly in patients with cuff-tear arthropathy. The 10-year survivals free of revision surgery and glenoid loosening were 91% and 84%; however, there was a functional deterioration over time, with less than 60% survivorship of an absolute Constant score over 30 points. These authors hypothesized occult aseptic glenoid loosening as a possible explanation for the functional deterioration over time. The influence of the underlying diagnosis on the expected outcome has been noted by several authors. Boileau et al.4 reported on 45 reverse arthroplasties performed for cuff-tear arthropathy (21), sequelae of fracture (5), and revision shoulder arthroplasty (19). The complication rate was 24%, including dislocation (3), deep infection (3), humeral aseptic loosening (1), periprosthetic fractures (3), late acromial fractures (2), and axillary nerve palsy (1). There were better results and fewer complications in the group of patients with cuff-tear arthropathy. Similar finding were reported by Wall et al.41: in a larger series of 240 reverse shoulder

26

arthroplasties; worse results were reported when reverse arthroplasty was used for revision surgery. Klein et al.25 reported good results in 20 patients treated with a reverse prosthesis for a displaced proximal humerus fracture. Elevation averaged 123 degrees, the mean ASES and Constant scores were 68 points, and the mean DASH score was 47 points. Promising results have also been reported by others for this particular indication.42 Dr. Frankle's group has reported on the results obtained using a reverse prosthesis with a lateral center of rotation. In 2005, these authors reported a minimum 2-year follow-up study of 60 shoulders with cuff-tear arthropathy.12 Reverse arthroplasty was associated with statistically significant improvements in pain and function, with a mean active elevation of approximately 105 degrees. However, there was a 17% complication rate and a 12% rate of revision for implant failure. Some features of the implant were modified to improve screw fixation of the glenoid component, and the results of the new version of this implant have been reported recently. Cuff et al.9 reported on 96 shoulders followed up for a minimum of 2 years with similar improvements in pain and function but no cases of either mechanical failure of the glenoid or notching. These same authors have reported a reasonable rate of satisfactory results using this implant in difficult indications such as failed hemiarthroplasty associated with cuff deficiency,28 failed hemiarthroplasty for proximal humerus fractures,27 and deep periprosthetic infection.10

COMPLICATIONS Reverse shoulder arthroplasty is commonly used for the salvage of difficult problems such as failed prosthesis with an

27

absent cuff or cuff-tear arthropathy with anterosuperior instability. In addition, this implant design is selectively used in older patients with more osteopenia, and the results to date reflect mostly the initial experience with reverse arthroplasty. For all these reasons, the complications rates reported in the literature are high and have stimulated refinements in design and surgical technique. The main complications of reverse arthroplasty have included infection, dislocation, intraoperative fractures, brachial plexopathy, acromial stress fractures, glenoid notching, and different modes of mechanical failure.4 , 12 , 14 , 17 , 35 , 37 , 44 Despite being a relatively constrained implant, dislocation may complicate reverse shoulder arthroplasty (Fig. 30.9). Many authors believe that dislocation of a reverse prosthesis happens with the arm in adduction and extension. The main factors contributing to dislocation may include component malposition, inadequate soft tissue tension, severe compromise of the anterior soft tissue envelope, and impingement secondary to retained bone fragments or thickened capsule.14 , 43 Care should be taken at the time of surgery to eliminate any potential sources of impingement, optimize component position, and achieve adequate soft tissue tension. Closed reduction may be successful in some patients, but surgery is oftentimes needed to change the thickness of the polyethylene insert and address other factors implicated in each particular patient. Some designs provide a metal augment to increase the height of the humeral component without revising the stem. So-called retentive deeper polyethylene inserts also provide additional stability but increase the risk of catastrophic polyethylene wear.

28

Intraoperative fractures may occur on the humeral side at the time of exposure in patients with severe preoperative stiffness and osteopenia, especially in the revision setting. The proximal humerus may also be fractured by retractors and the time of glenoid exposure; it is recommended not to complete the humeral preparation until the glenoid component is implanted to protect the proximal humerus bone stock. Glenoid fractures may occur during preparation of the glenoid, especially reaming, and may prevent component implantation. Brachial plexopathy may occur as a result of lengthening. Some studies have estimated between a 15% and a 20% increase in strain on the medial and lateral roots of the median nerve, with implantation of a reverse prosthesis.39 As opposed P.282

to plexopathies complicating anatomic replacement, which most likely occur secondary to transient stretching during surgery, the increased tension on the brachial plexus may be more permanent with reverse arthroplasty, although a different rate of spontaneous recovery has not been reported.

29

FIGURE 30.9 Dislocation after reverse total shoulder arthroplasty. Inadequate soft tissue tension was found to be main contributing factor to the dislocation in this particular patient.

Acromial stress fractures may be present prior to surgery in patients with cuff-tear arthropathy. Increased tension on the deltoid after reverse prosthesis may also lead to postoperative stress fractures, which usually present as pain and decreased active elevation.41 Surgical treatment is unpredictable and rarely recommended. Nonoperative treatment may lead to resolution of the pain, but some patients will continue to complain of poor function. Fractures

30

affecting the spine of the scapula are uncommon and difficult to diagnose but may severely compromise the outcome. As mentioned before, scapular notching refers to progressive bone resorption at the inferior aspect of the glenoid secondary to repetitive impingement.26 Notching does not seem to occur with reverse designs with a lateralized center of rotation.9 Notching is concerning as bone loss could potentially lead to glenoid loss of fixation. Levigne et al.26 reported a 62% rate of scapular notching in a consecutive series of 337 shoulders followed for an average of 4 years. Notching was associated with length of follow-up, cuff-tear arthropathy, infraspinatus atrophy, a superior approach, and superior orientation of the glenoid. Notching was also correlated with both humeral and glenoid radiolucent lines. Different modes of implant failure have been recognized after reverse arthroplasty. Glenosphere disengagement has been reported mostly with the initial Delta III and the Aequalis designs.31 As mentioned above, disengagement of the Delta III modular humeral component has been reported in the absence of proximal humeral bone support. Loosening of the lengthening for the humeral component has also been reported.5 Finally, polyethylene dissociation has also been reported.14 Improvements in the design of the glenoid component and the development of monoblock humeral components are expected to eliminate these failure modes. Mechanical failure of the glenoid component may represent the limiting factor of the long-term survivorship of reverse arthroplasty. Improvements in implant design will likely translate in decreased rates of glenoid failure. However, bone-implant interface is subjected to substantial stress in patients with already compromised bone stock secondary to

31

osteopenia, progressive glenoid erosion, or previous surgery. Longer follow-up studies are needed to determine the mechanical failure rate of the glenoid component with widespread use.

SUMMARY Reverse shoulder arthroplasty has emerged as a promising reconstructive alternative for patients with cuff-tear arthropathy and several other difficult shoulder problems. Improvements in design and surgical technique have allowed refinement of the procedure. The early results are usually impressive, with excellent pain relief and good active motion in patients with very poor preoperative shoulder function. However, not every patient obtains excellent motion, and complications may occur, including dislocation, brachial plexopathy, acromial stress fracture, scapular notching, and mechanical failure of the reconstruction. Further long-term studies are needed to fully understand the limitations of these designs and their survivorship.

References 1. Boileau P, Chuinard C, Roussanne Y, et al: Modified latissimus dorsi and teres major transfer through a single delto-pectoral approach for external rotation deficit of the shoulder: as an isolated procedure or with a reverse arthroplasty. J Shoulder Elbow Surg 16(6):671-682, 2007. 2. Boileau P, Chuinard C, Roussanne Y, et al: Reverse shoulder arthroplasty combined with a modified latissimus dorsi and teres major tendon transfer for shoulder pseudoparalysis associated with dropping arm. Clin Orthop Relat Res 466(3):584-593, 2008.

32

3. Boileau P, Watkinson DJ, Hatzidakis AM, Balg F: Grammont reverse prosthesis: design, rationale, and biomechanics. J Shoulder Elbow Surg 14(1 Suppl S): 147S161S, 2005. 4. Boileau P, Watkinson D, Hatzidakis AM, Hovorka I: Neer Award 2005: The Grammont reverse shoulder prosthesis: results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15(5):527-540, 2006. 5. Boons HW, van Loon CJ, Rijnberg WJ: Lengthener loosening in a reversed shoulder prosthesis: a case report. Acta Orthop Belg 74(5):689-692, 2008. 6. Boudreau S, Boudreau ED, Higgins LD, Wilcox RB III: Rehabilitation following reverse total shoulder arthroplasty. J Orthop Sports Phys Ther 37(12):734-743, 2007. 7. Chebli C, Huber P, Watling J, et al: Factors affecting fixation of the glenoid component of a reverse total shoulder prothesis. J Shoulder Elbow Surg 17(2):323-327, 2008. 8. Codsi MJ, Iannotti JP: The effect of screw position on the initial fixation of a reverse total shoulder prosthesis in a glenoid with a cavitary bone defect. J Shoulder Elbow Surg 17(3):479-486, 2008. 9. Cuff D, Pupello D, Virani N, et al: Reverse shoulder arthroplasty for the treatment of rotator cuff deficiency. J Bone Joint Surg Am 90(6):1244-1251, 2008. 10. Cuff DJ, Virani NA, Levy J, et al: The treatment of deep shoulder infection and glenohumeral instability with debridement, reverse shoulder arthroplasty and postoperative antibiotics. J Bone Joint Surg Br 90(3):336-342, 2008. 11. Favre P, Loeb MD, Helmy N, Gerber C: Latissimus dorsi transfer to restore external rotation with reverse shoulder

33

arthroplasty: A biomechanical study. J Shoulder Elbow Surg 17(4):650-658, 2008. 12. Frankle M, Siegal S, Pupello D, et al: The Reverse Shoulder Prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 87(8):16971705, 2005. 13. Franklin JL, Barrett WP, Jackins SE, Matsen FA III: Glenoid loosening in total shoulder arthroplasty. Association with rotator cuff deficiency. J Arthroplasty 3(1):39-46, 1988. 14. Garberina MJ, Williams GR Jr: Polyethylene dissociation after reverse total shoulder arthroplasty: The use of diagnostic arthroscopy. J Shoulder Elbow Surg 17(1):e16e18, 2007. 15. Gerber C, Pennington SD, Lingenfelter EJ, Sukthankar A: Reverse Delta-III total shoulder replacement combined with latissimus dorsi transfer. A preliminary report. J Bone Joint Surg Am 89(5):940-947, 2007. 16. Grammont PM, Baulot E: Delta shoulder prosthesis for rotator cuff rupture. Orthopedics 16(1):65-68, 1993. 17. Guery J, Favard L, Sirveaux F, et al: Reverse total shoulder arthroplasty. Survivorship analysis of eighty replacements followed for five to ten years. J Bone Joint Surg Am 88(8):1742-1747, 2006. 18. Gutierrez S, Comiskey CA, Luo ZP, et al: Range of impingement-free abduction and adduction deficit after reverse shoulder arthroplasty. Hierarchy of surgical and implant-design-related factors. J Bone Joint Surg Am 90(12):2606-2615, 2008. 19. Gutierrez S, Greiwe RM, Frankle MA, et al: Biomechanical comparison of component position and hardware failure in the

34

reverse shoulder prosthesis. J Shoulder Elbow Surg 16(3 Suppl):S9-S12, 2007. 20. Gutierrez S, Keller TS, Levy JC, et al: Hierarchy of stability factors in reverse shoulder arthroplasty. Clin Orthop Relat Res 466(3):670-676, 2008. 21. Gutierrez S, Levy JC, Frankle MA, et al: Evaluation of abduction range of motion and avoidance of inferior scapular impingement in a reverse shoulder model. J Shoulder Elbow Surg 90(12):2606-2615, 2008. 22. Harman M, Frankle M, Vasey M, Banks S: Initial glenoid component fixation in “reverse” total shoulder arthroplasty: a biomechanical evaluation. J Shoulder Elbow Surg 14(1 Suppl S):162S-167S, 2005. 23. Humphrey CS, Kelly JD II, Norris TR: Optimizing glenosphere position and fixation in reverse shoulder arthroplasty, Part Two: The three-column concept. J Shoulder Elbow Surg 17(4):595-601, 2008. 24. Kelly JD II, Humphrey CS, Norris TR: Optimizing glenosphere position and fixation in reverse shoulder arthroplasty, Part One: The twelve-mm rule. J Shoulder Elbow Surg 17(4):589-594, 2008. P.283

25. Klein M, Juschka M, Hinkenjann B, et al: Treatment of comminuted fractures of the proximal humerus in elderly patients with the Delta III reverse shoulder prosthesis. J Orthop Trauma 22(10):698-704, 2008. 26. Levigne C, Boileau P, Favard L, et al: Scapular notching in reverse shoulder arthroplasty. J Shoulder Elbow Surg 17(6):925-935, 2008.

35

27. Levy J, Frankle M, Mighell M, Pupello D: The use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty for proximal humeral fracture. J Bone Joint Surg Am 89(2):292-300, 2007. 28. Levy JC, Virani N, Pupello D, Frankle M: Use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty in patients with glenohumeral arthritis and rotator cuff deficiency. J Bone Joint Surg Br 89(2):189-195, 2007. 29. Martin TG, Iannotti JP: Reverse total shoulder arthroplasty for acute fractures and failed management after proximal humeral fractures. Orthop Clin North Am 39(4):451457, vi, 2008. 30. Middernacht B, De Roo PJ, Van Maele G, De Wilde LF: Consequences of scapular anatomy for reversed total shoulder arthroplasty. Clin Orthop Relat Res 466(6):14101418, 2008. 31. Middernacht B, De Wilde L, Mole D, et al: Glenosphere disengagement: a potentially serious default in reverse shoulder surgery. Clin Orthop Relat Res 466(4):892-898, 2008. 32. Rittmeister M, Kerschbaumer F: Grammont reverse total shoulder arthroplasty in patients with rheumatoid arthritis and nonreconstructible rotator cuff lesions. J Shoulder Elbow Surg 10(1):17-22, 2001. 33. Sanchez-Sotelo J, Cofield RH, Rowland CM: Shoulder hemiarthroplasty for glenohumeral arthritis associated with severe rotator cuff deficiency. J Bone Joint Surg Am 83A(12):1814-1822, 2001. 34. Sanchez-Sotelo J, O'Driscoll SW, Torchia ME, et al: Radiographic assessment of cemented humeral components

36

in shoulder arthroplasty. J Shoulder Elbow Surg 10(6):526531, 2001. 35. Seebauer L: Total reverse shoulder arthroplasty: European lessons and future trends. Am J Orthop 36(12 Suppl 1):22-28, 2007. 36. Simovitch RW, Helmy N, Zumstein MA, Gerber C: Impact of fatty infiltration of the teres minor muscle on the outcome of reverse total shoulder arthroplasty. J Bone Joint Surg Am 89(5):934-939, 2007. 37. Sirveaux F, Favard L, Oudet D, et al: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br 86(3):388-395, 2004. 38. Terrier A, Reist A, Merlini F, Farron A: Simulated joint and muscle forces in reversed and anatomic shoulder prostheses. J Bone Joint Surg Br 90(6): 751-756, 2008. 39. Van Hoof T, Gomes GT, Audenaert E, et al: 3D computerized model for measuring strain and displacement of the brachial plexus following placement of reverse shoulder prosthesis. Anat Rec (Hoboken) 291(9):1173-1185, 2008. 40. Virani NA, Harman M, Li K, et al: In vitro and finite element analysis of glenoid bone/baseplate interaction in the reverse shoulder design. J Shoulder Elbow Surg 17(3):509521, 2008. 41. Wall B, Nove-Josserand L, O'Connor DP, et al: Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg Am 89(7):1476-1485, 2007. 42. Wall B, Walch G: Reverse shoulder arthroplasty for the treatment of proximal humeral fractures. Hand Clin 23(4):425430, 2007.

37

43. Werner CM, Steinmann PA, Gilbart M, Gerber C: Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total shoulder prosthesis. J Bone Joint Surg Am 87(7):14761486, 2005. 44. Wierks C, Skolasky RL, Ji JH, McFarland EG: Reverse total shoulder replacement: intraoperative and early postoperative complications. Clin Orthop Relat Res 467(1):225-234, 2009.

38

Chapter 31A Acute Fractures: Fixation and Arthroplasty Michael E. Torchia During the past several years, thinking about the operative treatment of fractures of the proximal humerus has changed. There is now a trend toward more fracture fixation and less arthroplasty. This change in practice has been driven by several factors including (a) The recognition that humeral head replacement for acute fractures has an unpredictable outcome and may not be a durable solution in younger patients. (b) The understanding that posttraumatic avascular necrosis of the humeral head is not a clinical disaster.10 (c) More accurate preoperative imaging with three-dimensional computed tomography (3D CT). (d) Improved intraoperative imaging techniques with fluoroscopy. (e) Refined reduction maneuvers.3 , 8 , 13 (f) Improved implants (contoured locking plates). Although open reduction and internal fixation (ORIF) has become more popular, arthroplasty still has a role in the treatment of acute fractures, particularly in the elderly. Humeral component designs have been improved to facilitate trial reduction, anatomic reconstruction, and tuberosity healing. Additionally, reverse arthroplasty, which has been considered a salvage procedure, is now being applied to the management of selected acute fractures.14 Despite these advances, surgical treatment of acute proximal humerus fractures has a surprisingly high rate of complications.2 , 4 , 5 , 6 , 14 , 19 , 20 , 23 With ORIF, two problems, in particular, are responsible for the majority of reported

1

reoperations: varus reductions1 and screw penetration beyond the subchondral bone of the humeral head.5 Both of these problems can be avoided with attention to good surgical technique. In contrast, good surgical technique with humeral head replacement does not consistently result in tuberosity healing.15 Seemingly, this is a biological problem: regardless of technique, bone tends not to heal to metal or cement. Although the tuberosities can be advanced distally to allow greater surface contact with the shaft, this results in mechanical aberrations and poor function.12 This problem has prompted a growing interest in ORIF and in some situations, reverse arthroplasty for acute fractures.14

INDICATIONS Neer's guidelines published almost 40 years ago remain useful.16 , 17 Minimally displaced “one-part” fractures are treated conservatively. Displaced fractures are typically treated with surgery except when the anticipated demands on the extremity are very low. In this setting, it seems reasonable to allow a displaced fracture to malunite and accept motion loss due to tuberosity impingement. Most twoand three-part fractures (even in patients with poor bone quality) can now be reliably fixed utilizing modern methods. Selected four-part fractures can also be treated with ORIF.7 , 21 , 23 Arthroplasty is generally reserved for unreconstructable fractures in the elderly. Humeral head replacement is now used only occasionally in our practice when the rotator cuff is present and the fracture cannot be fixed. The role of the reverse prosthesis for acute fractures is evolving. At this time, it seems reasonable to consider reverse arthroplasty in the setting of an elderly patient with

2

low demands, an unreconstructable fracture, severe rotator cuff disease, and a functioning deltoid.

SURGICAL TECHNIQUE: ORIF Preoperative Planning Good surgical results begin with a sound preoperative plan. A comparison x-ray of the opposite shoulder has great value when assessing the quality of the intraoperative reduction. Although there is individual variation in the anatomy of the proximal humerus, major side-to-side differences are uncommon. If we recall that one of the most common problems reported with ORIF is varus malreduction,1 then the practice of using the contralateral shoulder x-ray as a template is advisable (Fig. 31A.1A-C). 3D CT can also be useful when trying to understand the geometry of more complex fractures and fracture-dislocations. Subtraction views demonstrate bony Bankart lesions and articular fractures of the humeral head that might otherwise have been difficult to appreciate depending upon the plane of the x-ray beam or two-dimensional image. 3D CT also answers a critical question in surgery for three- and four-part fractures: what if any part of greater or lesser tuberosity is attached to the head segment? This area serves as a handle to reduce the head segment with traction sutures placed at the bone-tendon junction of the rotator cuff: the so-called string puppet technique. With the advent of 3D CT, it is now possible to plan the exposure, reduction maneuvers, position of the hardware, and anticipate the occasional need for bone grafting (Fig. 31A.2A-D).

3

OPERATING ROOM SETUPFLUOROSCOPY Optimal room setup allows unrestricted access to the shoulder for fluoroscopic imaging. Many methods have been proposed; however, most surgeons prefer using a standard operating table and some variation of the familiar beach chair position. After induction of anesthesia, the table is turned 90 degrees so that the injured shoulder is opposite the anesthesia team and equipment. This allows access for the C-arm to enter and exit the field from the head of the bed (Fig. 31A.3A-C). Regardless P.285

P.286

of the preferred setup and patient positioning, it is wise to verify the ability to obtain high-quality fluoroscopic views prior to draping.

4

FIGURE 31A.1 A: An AP x-ray demonstrating a two-part fracture in a 95-year-old woman. B: AP external rotation view taken at follow-up. C: Comparison AP external rotation view contralateral shoulder. The uninjured side served as a template for

5

reduction. Despite shortening to gain stability, the neck shaft angle and position of the greater tuberosity have been restored.

FIGURE 31A.2 A: A 3D CT demonstrating a fracture-dislocation in an 87-year-old woman. The CT scan-aided planning of the surgical exposure and position of the implants. In this case, an anterior arthrotomy was done to access the glenoid rim fracture, which was addressed with suture fixation (B). Additionally, the pectoralis major tendon was divided and then repaired after placement of a minifragment “antiglide” plate along the medial aspect of the humerus (C). Follow-up clinical photograph demonstrating satisfactory motion (D).

6

EXPOSURE The extended deltopectoral approach as described by Neer18 is used. The entire interval from the clavicle to the deltoid insertion is developed preserving the muscle origin and releasing a portion of the insertion as needed. The subdeltoid space is mobilized taking care to avoid the terminal branches of the axillary nerve. A Brown deltoid retractor is placed. Abduction of the arm relaxes the deltoid and allows access to the entire greater tuberosity and rotator cuff. During exposure and placement of hardware, every attempt is made to respect the primary blood supply to the humeral head by avoiding the anterior circumflex vessels as they course along the subscapularis, and the arcuate artery as it courses along the bicipital groove.

EXTENSILE MANEUVERS Occasionally, fractures of the proximal humerus extend into the diaphysis. In this situation, the exposure is carried distally (Henry approach), the radial nerve is identified, and a long P.287

plate is applied to the lateral aspect of humerus. This necessitates release of the deltoid insertion, which does not seem to cause any clinical sequelae in the absence of a brachial plexopathy.11 Conversely, deep dissection can be extended proximally and medially to enter the glenohumeral joint to address a humeral head articular fracture or a glenoid rim fracture. This is accomplished by opening the rotator interval and performing an anterior arthrotomy, taking care to limit the distal extent of the subscapularis tenotomy to preserve the anterior circumflex vessels.

7

FIGURE 31A.3 The method of fluoroscopically obtaining images in the operating room. A: The beam is directed perpendicular to the scapula and the arm is held in external rotation. B: The velpeau axillary view with the arm held in internal rotation. C: The standard axillary view.

REDUCTION MANEUVERS Reduction maneuvers are logical: impacted fractures are disimpacted (Fig. 31A.4),13 , 21 and unimpacted fractures are impacted (Fig. 31A.5).3 In the common unimpacted two- and three-part fracture patterns, strategic placement of sutures

8

serves to reduce the typical varus and apex anterior angulation.3 It should be noted that the valgus impaction osteotomy has definite limitations. Excessive shortening (>1 cm) can occur in cases with severe metaphyseal comminution. While shortening greater than 1 cm may be tolerated in some patients with simple fractures, others can experience anteriorinferior instability. This is particularly problematic in the setting of a fracture-dislocation with a glenoid rim fracture, an axillary neuropathy, and/or a coracoid fracture. In these situations, in order to avoid inferior instability, humeral length is restored with anatomic reduction (Fig. 31A.2). When necessary in these cases, bone loss is treated with grafting (typically an intramedullary allograft fibula). A similar approach is used in cases with severe metaphyseal comminution where impaction without grafting could cause excessive shortening.

HUMERAL HEAD SUPPORT The concept of head support has been emphasized by several authors.3 , 9 , 22 Most often, support of the head segment is P.288

achieved with the shaft of the humerus. In cases with moderate or severe traumatic bone loss, bone graft or a bone graft substitute is used. If the soft humeral head is supported only by rigid hardware, it tends to settle on the metal with resultant “secondary screw cutout,”5 a frequently reported cause for reoperation.5 , 6 , 19 , 23

9

FIGURE 31A.4 A: An AP x-ray demonstrating a valgus impacted four-part fracture. The head was elevated using a using a square tipped impactor placed through a coronal split in the greater tuberosity (B).

PROVISIONAL FIXATION After the initial reduction, provisional fixation is achieved with a pin or pins placed just posterior to the long head biceps tendon to avoid interference with the plate, which will later occupy the lateral surface of the proximal humerus. The traction sutures are then tensioned and tied to the pin (Fig. 31A.6). This form of robust temporary tension band fixation suture allows the arm to be rotated so that the reduction can be assessed in multiple planes with fluoroscopy.

10

FIGURE 31A.5 The valgus impaction osteotomy described by Banco. Note the long head biceps is used to assess rotation of the reduction. Balanced compression is achieved slightly trimming sharp edges anteriorly and laterally. The “trimmings” are used as bone graft to further support the humeral head.

ASSESSMENT OF REDUCTION Although reduction maneuvers are well established, methods for assessing the reduction have not been emphasized. On the external rotation view, the shaft should be under the head, the greater tuberosity should be approximately 5 to 10 mm below the top of the head, and the articular surface should point toward the glenoid (Robert H. Cofield: Personal communication) (Fig. 31A.7). More precision can be added by referencing the image of the opposite shoulder. Within reason, an attempt is made to restore the tuberosity height and neck-shaft angle of the opposite shoulder (Fig. 31A.1). If there is any doubt, it seems advisable to error on the side of valgus rather than varus. The internal rotation view and 11

axillary views are used to assess translation and angulation of the shaft relative to the head, the position of the lesser tuberosity, and the position of the head P.289

segment relative to the glenoid. At this point, adjustments to the reduction are made, as needed. This is the best time to scrutinize the reduction, before the hardware is placed.

FIGURE 31A.6 The method of provisional pin and tension band suture fixation. Traction sutures are tensioned and tied to the pin.

12

FIGURE 31A.7 A fluoroscopic image demonstrating a provisional reduction. Note the arm is in external rotation. In this case, a small amount of bone graft substitute was used to help support the humeral head.

DEFINITIVE FIXATION Next, a precontoured locking plate is applied laterally (Fig. 31A.8) and held with a push-pull reduction device or “whirlybird.” Hardware position is assessed mainly on the external rotation view (Fig. 31A.9). If the plate is positioned too high, impingement will occur. If the plate is too low, screw trajectory can be suboptimal. It is important to note that the plate is applied to the fracture that is already reduced and 13

compressed. Gaps between the plate and the bone in the metadiaphysis are accepted. No attempt is made to contour the plate. This technique is very different than using the plate as a reduction tool. This is a key concept. Pulling the bone to the plate with screws or sutures tends to leave the head unsupported and at risk for varus drift and/or secondary screw penetration.1 , 5 Once plate position is optimal, screws are placed (Fig. 31A.10). When placing screws in the humeral head, only the outer cortex is drilled. The depth gauge is then gently advanced into the osteoporotic bone under fluoroscopy to measure length. Again, it is important to understand that if the head is supported and tension band sutures are used, it is not necessary to engage the subchondral bone of the head. Placing shorter screws lowers the risk of screw penetration, another common cause for reoperation.5 After plate application, the provisional fixation is removed and at least four definitive tension band sutures are placed using any open holes in the plate as an anchor points (Fig. 31A.11). Next, the shoulder is carefully assessed for position of the hardware and motion. If the fluoroscopic examination identifies any screws in the subchondral bone, these are shortened. The passive motion of the shoulder is then recorded and included in the operative note for later reference during rehabilitation. P.290

Closure is routine although monofilament absorbable sutures are recommended due to the theoretical advantage of reduced bacterial adherence.

14

FIGURE 31A.8 A lateral view of the proximal humerus. The provisional fixation leaves the lateral surface of the humerus empty and does not interfere with application of the plate.

15

FIGURE 31A.9 An AP fluoroscopic image demonstrating plate positioning.

16

FIGURE 31A.10 An AP fluoroscopic image demonstrating a method of screw placement that minimizes risk of primary or secondary penetration. The arm is rotated under the fluoroscopy machine to check screw length in multiple planes.

17

FIGURE 31A.11. An intraoperative photograph demonstrating the final construct. Heavy monofilament absorbable tension band sutures are applied liberally using empty holes in the plate as anchor points. It is preferable to use smooth holes when possible to minimize the risk of suture abrasion.

AFTERCARE The timing of motion exercises depends on bone quality and fixation. In younger patients with good bone quality supine passive range-of-motion exercises are initiated the day after surgery. A physical therapist teaches a family member how to perform gentle supine passive as tolerated with limits: external rotation to neutral and elevation to 90 degrees. When patients return at 3 weeks for staple removal, the limits are advanced to the degree of motion that was possible at surgery (usually ~45 degrees of external rotation and 160 degrees of elevation). At 6 weeks, the program is changed to active assisted range of motion with the goal of achieving motion similar to the contralateral side by the 3-month mark 18

at which time x-rays usually demonstrate consolidation of the fracture (Fig. 31A.12). At this point, active motion is encouraged and patients are instructed to begin using the arm for light daily activities including driving and shopping. More forceful activities, such as yardwork, tennis, or golf, are avoided for 6 months.

FIGURE 31A.12. A 3-month follow-up x-ray demonstrating consolidation of the fracture.

For patients with poor bone quality: A variation of Neer's limited goals program is used.18 During the first 6 weeks after surgery, patients are directed to wear a sling fulltime.

19

After 6 weeks, the program is the same for patients with good bone quality.

SURGICAL TECHNIQUE HHR The method of preoperative planning, room setup, and exposure is nearly identical to ORIF. An x-ray of the opposite shoulder is used for templating. At surgery, the segments of the fracture are reduced and fixed temporarily with pins. This method, suggested by Flatow (Evan Flatow: personal communication), allows the surgeon to accurately assess the position of the native head and tuberosities. This information is then used to position the prosthetic head and reconstruct the tuberosities. Many HHR systems now include guides to allow trial reduction. Adjustments in prosthetic position are made as needed and the canal is prepared for cementation. Cement fixation has the advantage of immediate stability but may impair tuberosity healing due to the local effect of thermal necrosis. It seems best to avoid the practice of overfilling the metaphyseal tube with cement to allow room for bone grafting. Bone is harvested from the head segment and placed beneath the tuberosities prior to definitive suture fixation. Tuberosity reconstruction does not need to be overly complex. The preferred method is that of Boileau fixing the greater and lesser tuberosities sequentially with cerclage sutures to compress the tuberosities (Fig. 31A.13). Aftercare is the same as for ORIF in patients with poor bone quality with emphasis on healing and stability rather than motion.

20

FIGURE 31A.13. Tuberosity fixation: the method of Boileau.

P.291

21

FIGURE 31A.14. A representative HHR case complicated by tuberosity resorption.

22

A: Intraoperative fluoroscopy demonstrating a 4-part fracture in an 84-year-old woman. B-E: Despite the use of a specialized implant, accurate, secure reconstruction of the tuberosities, and bone grafting, the greater tuberosity did not heal. The patient experienced severe pain and weakness requiring conversion to a reverse arthroplasty.

P.292

MAYO RESULTS Humeral Head Replacement Fifty-seven shoulders were reviewed after a minimum of 5 years. According to the modified Neer rating system, results were satisfactory in 27 patients and unsatisfactory in 30. The mean active elevation was 100 degrees and ER was 30 degrees. Eighty-four percent of patients reported mild or no pain.2 As in most series, tuberosity migration and resorption were the primary problems leading to poor function (Fig. 31A.14A-E). The authors concluded that “current indications, surgical technique, and postoperative treatment may need to be revisited.”

ORIF WITH LOCKING PLATES: INITIAL EXPERIENCE The results of the first 16 cases of locking plate fixation done at Mayo were recently reported.22 This series represents our painful learning curve: four of the 16 cases did not heal, and three required reoperation within 1 year. In retrospect, these poor results were due to technical errors, overconfidence in the locking plate technology, and grossly inadequate distal fixation. Since that time, longer plates have become available and are now used in cases with diaphyseal extension. 23

Perhaps the most important finding in this study was incidental: older patients seemed to fair better than the younger patients. This finding prompted a critical analysis. When treatment of older patients was compared to the younger group, we found four key differences: (a) In general, the elderly had nonanatomic reductions using the so-called valgus impaction osteotomy of Fenlin.3 This method allows balanced compression of the head on the shaft. (b) In the elderly group, emphasis was placed on support of the humeral head with the shaft and/or bone graft.3 , 8 (c) Tension band sutures were used liberally to neutralize the forces of the rotator cuff.3 (d) In the elderly, motion was delayed for a period of 6 weeks.16 , 17 , 18 This method has been called the “hybrid technique” because concepts were borrowed from multiple sources and combined with locking plate technology. Results of this method are outlined below.

ORIF: GERIATRIC CASES During a 5-year period (2002-2007), 23 patients, aged 75 to 97, underwent ORIF of proximal humerus fractures using the so-called hybrid technique method. The results were reviewed after a minimum of 1 year (12-36 months, mean 28 months). There were ten two-part factures, ten three-part fractures, and three impacted patterns. All fractures healed, and all patients were able to perform daily activities independently. The mean elevation was 140 degrees and the mean external rotation was 42 degrees. No patients developed avascular necrosis. There were no infections, fixation failures, or reoperations.24 These data suggest that advanced age is not a contraindication to ORIF, and that a brief period of

24

postoperative immobilization does not seem to cause disabling stiffness in this patient group.

SUMMARY With a sound preoperative plan and attention directed to good surgical technique, most displaced proximal humerus fractures can be reliably fixed. Key elements include highquality fluoroscopic imaging, accurate reductions, support of the humeral head, locking plate fixation, and generous tension band suturing. In cases where fixation is not possible, humeral head replacement or reverse arthroplasty can be considered.

References 1. Agudelo J, Schurmann M, Stahel P, et al: Analysis of efficacy and failure in proximal humerus fractures treated with locking plates. J Orthop Trauma 21:676-681, 2007. 2. Antuna S, Sperling JW, Cofield RH: Shoulder hemiarthroplasty for acute fractures. J Shoulder Elbow Surg 17:202-209, 2008. 3. Banco SP, Andrisani D, Ramsey M, et al: Tension band fixation for unstable two-part humeral fractures in patients with osteopenic bone (parachute technique). Tech Shoulder Elbow Surg 2:50-53, 2001. 4. Boleuau P, Krishnan SG, Tinsi L, et al: Tuberosity malposition and migration: Reasons for poor outcomes after hemiarthriopasty for displaced fractures of the proximal humerus. J Shoulder Elbow Surg 11:401-412, 2002. 5. Brunner F, Sommer C, Bahrs C, et al: Open reduction and internal fixation of proximal humerus fractures using a proximal humeral locked plate: A prospective multicenter analysis. J Orthop Trauma 23:163-172, 2009.

25

6. Egol KA, Ong CC, Walsh M, et al: Early complications in proximal humerus fractures (OTA Types 11) treated with locked plates. J Orthop Trauma 22:159-164, 2008. 7. Esser RD: Treatment of three- and four-part fractures of the proximal humerus with a modified cloverleaf plate. J Orthop Trauma 8:15-22, 1994. 8. Gardner MJ, Boraiah S, Helfet DL, Lorich DG: Indirect medial reduction and strut support of proximal humerus fractures using an endosteal implant. J Orthop Trauma 22:195-200, 2008. 9. Gardner MJ, Weil Y, Barker JU, et al: The importance of medial support in locked plating of proximal humerus fractures. J Orthop Trauma 21:185-191, 2007. 10. Gerber C, Hersche O, Berberat C: The clinical relevance of posttraumatic avascular necrosis of the humeral head. J Shoulder Elbow Surg 7:586-590, 1998. 11. Gill DR, Torchia ME: The spiral compression plate for proximal humeral shaft nonunion: a case report and description of a new technique. J Orthop Trauma 13:141-144, 1999. 12. Huffman GR, Itamura JM, McGarry MH, et al: Biomechanical assessment of inferior tuberosity placement during hemiarthroplasty for four-part proximal humerus fractures. J Shoulder Elbow Surg 17:189-196, 2008. 13. Jakob RP, Miniaci A, Anson PS, et al: Four-part valgus impacted fractures of the proximal humerus. J Bone Joint Surg 73B:295-298, 1991. 14. Klein M, Juschka M, Hinkenjann B, et al: Treatment of comminuted fractures of the proximal humerus in elderly patients with the Delta III Reverse shoulder prosthesis. J Orthop Trauma 22:698-704, 2008.

26

15. Loew M, Heitkemper S, Parsch D: Influence of the design of the prostheis on outcome after hemiarthroplasty of the shoulder in displaced fractures of the head of the humerus. JBJS Br 88-B, 345-50, 2006. 16. Neer CS II: Displaced proximal humeral fractures: I. Classification and evaluation. J Bone Joint Surg 52A:10771089, 1970. 17. Neer CS II: Displaced proximal humeral fractures: II. Treatment of three-part and four-part displacement. J Bone Joint Surg 52A:1090-1103, 1970. 18. Neer CS: Shoulder Reconstruction. Philadelphia: WB Saunders, 1990:170-173, 530. 19. Owsley KC, Gorczyca JT: Displacement and cut out after open reduction and locked plate fixation of humeral fractures. J Bone Joint Surg 90A;233-240, 2008. 20. Plausinis D, Kwon YW, Zuckerman JD: Complications of humeral head replacement for proximal humeral fractures. Instr Course Lect 54:371-380, 2005. 21. Robinison CM, Page RS: Severely impacted valgus proximal humerus fractures. J Bone Joint Surg 86A:143-155, 2004. 22. Rose PS, Adams CR, Torchia ME, et al: Locking plate fixation for proximal humeral fractures: Initial results with a new implant. J Shoulder Elbow Surg 16:202-207, 2007. 23. Solberg BD, Moon CN, Franco DP, Paiement GD: Locked plating of 3- and 4-part proximal humerus fractures in older patients: The effect of initial fracture pattern on outcome. J Orthop Trauma 23:113-119, 2009. 24. Torchia ME: Technical tips for fixation of proximal humeral fractures in elderly patients. Chapter 44. In O'Connor

27

MI, Egol KA, Instructional Course Lectures Vol. 59. Rosemont, IL: AAOS; 2010. pp. 553-561.

28

Chapter 31B Shoulder Arthroplasty for Osteonecrosis Steven J. Hattrup The humeral head is second only to the femoral head in the frequency of occurrence of osteonecrosis.28 It is can be associated with a number of etiologic agents, the most common of which in our practice are trauma and corticosteroid use.19 Other potential causes include alcohol and tobacco abuse, dysbaric disease, Gaucher disease, sickle cell disease, radiation, and systemic lupus erythematosus, and hypercoagulopathy disorders.18 Frequently, the cause cannot be identified. Ultimately, osteonecrosis can lead to painful collapse of the articular surface of the humeral head and require prosthetic reconstruction or other surgical intervention.

ETIOLOGY The cause of posttraumatic osteonecrosis is understood best, wherein a traumatic insult disrupts the blood supply of the humeral head. The vascular anatomy of the proximal humerus has been well studied. The anterolateral ascending branch of the anterior humeral circumflex artery travels along the lateral aspect of the bicipital tendon and becomes intraosseous at the upper end of the bicipital groove, where it is termed the arcuate artery.16 , 23 Although Laing23 found a rich periosteal vascular network on the proximal humerus, there were few intraosseous anastomoses with the arcuate artery. Gerber elegantly confirmed the importance of the anterolateral ascending artery as the prime vascular supply to the humeral head16 (Fig. 31B.1). He also demonstrated that the posterior 1

humeral circumflex artery supplied only the posteriorinferior head and posterior greater tuberosity. More recently, Brooks and colleagues reexamined this issue in 16 cadaver shoulders.6 They found significant intraosseous anastomoses between the arcuate artery and posterior humeral circumflex artery, metaphyseal vessels, and vessels in the greater and lesser tuberosities. The anastomoses allow some perfusion to persist in fractures including the upper part of the neck with the head fragment. This potentially explains observations that three- and four-part fractures do not inevitably result in osteonecrosis.34 The pathogenesis of steroid induced osteonecrosis is less settled. Use of corticosteroids may effect alterations in fat metabolism, with fatty hypertrophy occurring in the marrow.8 , 18 This is postulated to result in increased intraosseous pressure, vascular occlusion, and ultimately avascular necrosis. An alternative theory involves the formation of fatty emboli from hyperlipidemia and fatty hypertrophy of the liver, which result in vascular occlusion and finally osteonecrosis. Other agents of fatty hypertrophy, including alcoholism or embolic phenomenon such as sickle cell disease, can result in osteonecrosis via similar pathways.

2

FIGURE 31B.1 Illustration of the vascular supply to the humerus head. 1. axillary artery; 2. posterior humeral circumflex artery; 3. anterior humeral circumflex artery; 4. ascending anterolateral ascending artery; 5. greater tuberosity; 6. lesser tuberosity; 8. entry point of the anterolateral branch into bone; 9. intertubercular groove. (From Gerber C: The arterial vascularization of the humeral head. J Bone Joint Surg 72A:1486-1494, 1990, with permission.)

CLASSIFICATION Cruess classified osteonecrosis of the humeral head with a staging system similar to that devised for the femoral head by Ficat and Arlet8 , 14 (Fig. 31B.2). Stage I disease is 3

preradiographic, with the disease typically diagnosed on magnetic resonance imaging. Mottled sclerosis is present on plain radiographs in Stage II disease. The sclerosis is caused by disruption of the normal bone remodeling process, producing thickened bone trabeculae surrounded by osteopenic regions. This sclerosis is generally found in the subarticular segment of the superocentral humeral head, and the articular surface remains intact in this stage. Progression to fatigue fracture of the subchondral P.294

bone is indicated by the presence of a crescent sign and marks Stage III disease. The articular surface may have mild flattening in this stage. Overt collapse and incongruity of the articular surface denote Stage IV, and Stage V is present when secondary degenerative changes set in.

4

FIGURE 31B.2 A,B: The five stages of osteonecrosis of the proximal humerus, as described by Cruess (1978).8 (See text for detailed explanation.)

NATURAL HISTORY The severity of the clinical course is dependent on the etiologic mechanism. The process appears to be relatively benign in sickle cell disease. Milner studied over 2500 patients with sickle cell, finding an overall incidence of 5

osteonecrosis in the humeral head of 5.6%.26 The prevalence was age related, with an incidence of 2.7% in those patients less than 25 years and increasing to 19.8% after age 35 years. Symptoms of pain and limitation of motion were found in just 21% of the study group, and only a single patient underwent replacement. David described a somewhat less favorable but still positive course in his series of 276 shoulders.10 The incidence of osteonecrosis was 14.8% at an average age of 25 years, and only two joint replacements were reported. Cruess in 1976 described the outcome in 18 patients with steroid-induced osteonecrosis.9 There were eight patients who had minimal deformity and only mild symptoms. Six other patients had more extensive deformity and more substantial pain. These patients suffered from limitation of activities. There were five shoulders in four patients who required humeral head replacement (HHR) for severe pain. All had successful results. L'Insalata et al.22 reported mixed results in a series of 65 shoulders in 42 patients. The most common etiology was steroid use, found in 52 shoulders. Thirty-five shoulders underwent replacement at an average of 2 years after initial presentation. The remaining 30 shoulders were reviewed at an average of 10 years. Fifteen shoulders had substantial symptoms, and the other fifteen were felt to have a satisfactory outcome. Thus 10 years after diagnosis, less than one of four patients were doing well. Poorer results were significantly related to more advanced disease (Stage III or higher). A trend toward better results in shoulders with a steroid etiology was not statistically significant.

6

Gerber et al.15 have examined the issue of posttraumatic osteonecrosis. At an average of 7.5 years after fracture, 25 shoulders were radiographically and clinically evaluated. Osteonecrosis was always associated with disability, but a significant relationship was found between outcome and anatomic reduction. Thirteen patients, with reduction within 2 mm, were compared to 12 patients, with proximal humeral malunion. Subjective outcome, pain, and range of motion were all superior in patients with more anatomic reduction. The authors felt that the end result for shoulders with osteonecrosis was equivalent to HHR for fracture treatment, provided anatomic reduction was initially obtained. Failure to achieve reduction increased the potential need for arthroplasty. Bastian found that humeral head ischemia does not always lead to a poor outcome.3 Evaluating a series of 51 consecutive patients treated with open reduction and internal fixation (ORIF) of a proximal humeral fracture, ten were judged to show ischemic changes on initial evaluation. Only two of the ten subsequently showed radiographic collapse, leading the authors to conclude preservation of the humeral head with ORIF to be worthwhile if technically feasible. The experience at the Mayo Clinic was examined, and the prognosis for posttraumatic osteonecrosis was found to be inferior to steroid-induced osteonecrosis.19 In 151 patients with 200 affected shoulders, the most common etiologies were corticosteroid use in 112 and trauma in 37. Ninety-seven shoulders required replacement at an average of less than 1 year after presentation. The need for arthroplasty was significantly more common with increased extent of head involvement, advancing stage of disease, and traumatic etiology. By 3 years after diagnosis, 77.8% of shoulders with

7

traumatic osteonecrosis had been replaced compared to 43.7% of those with a steroid etiology. Of those shoulders not replaced, 60 were followed for an average of 8.6 years. There was no to occasional moderate pain in 46 and moderate to severe pain in 14 patients. Motion in these shoulders, however, was well preserved, with mean values of 153° flexion, 134° abduction, and 63° external rotation. The majority of patients were able to maintain basic activities of daily living such as toileting and dressing, but more advanced activities such as overhead lifting and sports were generally impossible.

TREATMENT OPTIONS The favorable natural history for many patients makes it reasonable initially to treat patients conservatively, especially in steroid-induced osteonecrosis. Analgesic medication, activity modification, and gentle physical modalities are appropriate. Many patients have relatively mild symptoms and prolonged function of the shoulder even in more advanced stages of disease. However, if this is unsuccessful, surgery becomes a consideration. Core decompression is an option for earlier stage disease. While the early literature is mixed on this procedure, subsequent work is more encouraging. Neer30 had poor results P.295

with core decompression and bone grafting in two patients. L'Insalata et al.22 similarly had uniformly poor results in five shoulders. Four shoulders had Stage III disease, and the fifth was unspecified. Replacement was ultimately necessary for

8

all patients. Mont and associates described more extensive experience in a series of 30 shoulders.27 Utilizing the UCLA score, all 14 shoulders with Stage I or II disease had excellent or good outcomes. Of the ten shoulders with Stage III disease, seven had excellent and three poor outcomes. This group has continued to publish their growing experience with excellent results for earlier stage disease.24 , 28 At a 6year average follow-up, 74 of 95 (78%) shoulders had a successful outcome.28 Success was achieved in 15 of 16 (94%) shoulders with Stage I disease, 34 of 37 (92%) with Stage II, and 24 of 34 (71%) in Stage III but only 1 of 8 (13%) with Stage IV disease. These positive results support core decompression as a viable treatment alternative for early stage disease, especially in the younger patient. A number of technique articles have been published, describing arthroscopic-assisted core decompression with the use of an anterior cruciate ligament tibial guide as well as arthroscopic loose body removal.7 , 12 , 17 , 33 As the disease becomes more advanced, especially in an older patient, replacement becomes the most reliable option. Clearly arthroplasty should be considered for symptomatic Stage IV and Stage V disease. In Stage III disease, the decision can be more difficult. Radiographic findings may be subtle, yet symptoms may still be severe and only relieved by arthroplasty. Careful scrutiny of radiographic studies is essential. The crescent sign indicative of subchondral collapse with a cartilage flap detached from the underlying necrotic bone may be evident on only a single view or on computed tomography. With more extensive head involvement, advanced stage of disease, and a history of

9

trauma, the prognosis becomes poorer and the threshold to proceeding to replacement lower. The most common contraindications to replacement are active infection and the combination of rotator cuff and deltoid loss. Infection can be extremely subtle and the possibility must be considered whenever there has been prior surgery. Depending on the clinical circumstances, evaluation may include erythrocyte sedimentation rate and C-reactive protein levels, indium-111 scanning, and joint aspiration. The ultimate diagnosis may require intraoperative histology and cultures. The combination of deltoid loss and an irreparable rotator cuff is an indication for consideration of arthrodesis. Prosthetic replacement in this situation will not be functional.

RESULTS OF REPLACEMENT The outcome of replacement for osteonecrosis is often included with results for more common disorders such as osteoarthritis and traumatic arthritis. However, a number of authors have written of their results. In 209 cases scattered through fourteen articles, pain relief was typically excellent and range of motion varied from two thirds to near normal1 , 2 , 4 , 5 , 9 , 11 , 13 , 21 , 25 , 29 , 31 , 32 , 36 , 37 (Table 31B.1). The results of replacement for osteonecrosis at the Mayo Clinic have been published in two studies.20 , 35 Hattrup reported a series of 88 shoulders with replacement for osteonecrosis for various etiologies.20 At an average followup of almost 9 years, subjective improvement was expressed for 70 shoulders (79.5%) and no to occasionally moderate pain in 68 (77.3%). The mean American Shoulder and Elbow Surgeon (ASES) score was 63. Inferior results in both range of motion and ASES score were found in posttraumatic

10

osteonecrosis, with improved outcome in patients with a steroid-induced disease. Reconstruction in posttraumatic osteonecrosis can be complicated by the sequelae of the fracture injury and possible internal fixation, including scarring and stiffness of the rotator cuff and bony deformity. TABLE 31B.1 RESULTS OF REPLACEMENT FOR SHOULDER OSTEONECROSIS

Author (year)

Pain relief (%)

No. of cases

Active elevation (°)

Cruess (1976)9

5

100

101

Amstutz et al. (1988)1

3

100

160

Bade et al. (1984)2

8

100

170

Boyd et al. (1990)5

6

83

—

Boyd et al. (1991)4

11

100

119

Dines et al. (1993)11

3

100

128

Kay and Amstutz (1988)21

3

100

143

Neer et al. (1982)29

3

100

11

Rutherford and Cofield (1987)32

17

94

157

Warren et al. (1982)37

5

100

116

Feeley et al. (2008)13

67

Mansat et al. (2005)25

19

Orfaly et al. (2007)31

21

Tauber et al. (2007)36

38

127

95

107

123 90

VAPS 2.1

120

In the series by Hattrup, each physician chose glenoid resurfacing after evaluation of the degree of pathologic involvement. Little variation was discovered in the outcome of HHR and total shoulder arthroplasty (TSA), based on range of motion or ASES scores. Smith reported the long-term results of HHR for steroid-induced osteonecrosis.35 At 12-year mean follow-up, the average elevation was 139 degrees and external rotation 65 degrees. However, 12 (38%) of the shoulders were found to have moderate to severe pain. The Neer scores were 13 (42%), excellent; 4 (13%), satisfactory; and 14, (45%) unsatisfactory. A large number of unsatisfactory results were felt related to progressive glenoid wear over time. It remains the authors' practice to resurface 12

the glenoid if there is any significant articular cartilage damage.

SUMMARY Osteonecrosis of the humeral head is a common manifestation of a number of insults to the shoulder. Core decompression provides at least short- to medium-term relief of symptoms in earlier stage disease. With more advanced disease or in the elderly patient, shoulder arthroplasty can provide typically excellent pain relief with functional range of motion. HHR is chosen over TSA when the articular cartilage is well preserved on the glenoid. P.296

References 1. Amstutz HC, Thomas BJ, Kabo JM, et al: The DANA total shoulder arthroplasty. J Bone Joint Surg 70-A:1174-1182, 1988. 2. Bade HA, Warren RF, Ranawat CS, Inglis AE: Long term results of Neer total shoulder replacement. In Bateman JE, Welsh RP, (eds): Surgery of the Shoulder. Philadelphia, B. C. Decker, 1984, p 294. 3. Bastian JD, Hertel R. Initial post-fracture humeral head ischemia does not predict development of necrosis. J Shoulder Elbow Surg 17(1):2-8, 2008. 4. Boyd AD, Aliabadi P, Thornhill TS: Postoperative proximal migration in total shoulder arthroplasty. Incidence and significance. J Arthroplasty 6:31-37, 1991.

13

5. Boyd AD, Thomas WH, Scott RD, et al: Total shoulder arthroplasty versus hemiarthroplasty. Indications for glenoid resurfacing. J Arthroplasty 5: 329-336,1990. 6. Brooks CH, Revell WJ, Heatley FW: Vascularity of the humeral head after proximal humeral fractures. J Bone Joint Surg 73-B:132-136, 1993. 7. Chapman C, Mattern C, Levine WN. Arthroscopically assisted core decompression of the proximal humerus for avascular necrosis. Arthroscopy 20(9):1003-1006, 2004. 8. Cruess RL: Experience with steroid-induced avascular necrosis of the shoulder and etiologic considerations regarding osteonecrosis of the hip. Clin Orthop Relat Res 130:86-93, 1978. 9. Cruess RL: Steroid-induced avascular necrosis of the head of the humerus. Natural History and Management. J Bone Joint Surg 58-B:313-317, 1976. 10. David HG, Bridgman SA, Davies SG, et al: The shoulder in sickle-cell disease. J Bone Joint Surg 75-B:538-545, 1993. 11. Dines DM, Warren RF, Altcheck DW, Moeckel B: Posttraumatic changes of the proximal humerus: Malunion, nonunion, and osteonecrosis. Treatment with modular hemiarthroplasty or total shoulder arthroplasty. J Shoulder Elbow Surg 2:11-21, 1993. 12. Dines JS, Strauss EJ, Fealy S, Craig EV: Arthroscopicassisted core decompression of the humeral head. Arthroscopy 23(1):103e1-103e4, 2007. 13. Feeley BT, Fealy S, Dines DM, et al: Hemiarthroplasty and total shoulder arthroplasty for avascular necrosis of the humeral head. J Shoulder Elbow Surg 17(5):689-694, 2008.

14

14. Ficat RP: Idiopathic bone necrosis of the femoral head. Early diagnosis and treatment. J Bone Joint Surg 67-B:3-9, 1985. 15. Gerber C, Hersche O, Berberat C: The clinical relevance of posttraumatic avascular necrosis of the humeral head. J Shoulder Elbow Surg 7:586-590, 1998. 16. Gerber C: The arterial vascularization of the humeral head. J Bone Joint Surg 72-A:1486-1494, 1990. 17. Hardy P, Decrette E, Jeanrot C, et al: Arthroscopic treatment of bilateral humeral head osteonecrosis. Arthroscopy 16(3):332-335, 2000. 18. Hasan SS, Romeo M. Nontraumatic osteonecrosis of the humeral head. J Shoulder Elbow Surg 1(3):281-298, 2002. 19. Hattrup SJ, Cofield RH: Osteonecrosis of the humeral head: Relationship of disease stage, extent, and cause to natural history. J Shoulder Elbow Surg 8:559-564, 1999. 20. Hattrup SJ, Cofield RH: Osteonecrosis of the humeral head: Results of replacement. J Shoulder Elbow Surg 9:177182, 2000. 21. Kay SP, Amstutz HC: Shoulder hemiarthroplasty at UCLA. Clin Orthop Relat Res 228:42-48, 1988. 22. L'Insalata JC, Pagnani MJ, Warren RF, Dines DM: Humeral head osteonecrosis: Clinical course and radiographic predictors of outcome. J Shoulder Elbow Surg 5:355-361, 1996. 23. Laing PG: The arterial supply of the adult humerus. J Bone Joint Surg 38-A:1105-1116, 1956. 24. LaPorte DM, Mont MA, Mohan V, et al: Osteonecrosis of the humeral head treated by core decompression. Clin Orthop Relat Res 355:254-260, 1998.

15

25. Mansat P, Huser L, Mansat M, et al: Shoulder arthroplasty for atraumatic avascular necrosis of the humeral head: Nineteen shoulders followed for a mean of seven years. J Shoulder Elbow Surg 14(2):114-120, 2005. 26. Milner PF, Kraus AP, Sebes JI, et al: Osteonecrosis of the humeral head in sickle cell disease. Clin Orthop Relat Res 289:136-143, 1993. 27. Mont MA, Maar DC, Urquhart MW, et al: Avascular necrosis of the humeral head treated by core decompression. J Bone Joint Surg 75-B: 785-788, 1993. 28. Mont MA, Payman RK, LaPorte DM, et al: Atraumatic osteonecrosis of the humeral head. J Rheumatol 27(7):17661773, 2000. 29. Neer CS II, Watson KC, Stanton FJ: Recent experience in total shoulder replacement. J Bone Joint Surg 64-A:319337,1982. 30. Neer CS II: Shoulder Reconstruction. Philadelphia, WB Saunders Co., 1990. 31. Orfaly RM, Rockwood CA, Esenyel CZ, Wirth MA: Shoulder arthroplasty in cases with avascular necrosis of the humeral head. J Shoulder Elbow Surg 16(3S):27S-32S, 2007. 32. Rutherford CS, Cofield RH: Osteonecrosis of the shoulder [abstract]. Orthop Trans 11:239, 1987. 33. Sahajpal DT, Zuckerman JD: Core decompression for nontraumatic osteonecrosis of the humeral head. Bull NYU Hosp Jt Dis 66(2):118-119, 2008. 34. Schai P, Imhoff A, Preiss S: Comminuted humeral head fractures: A multicenter study. J Shoulder Elbow Surg 4:319330, 1995.

16

35. Smith RG, Sperling JW, Cofield RH, et al: Shoulder hemiarthroplasty for steroid induced osteonecrosis. J Shoulder Elbow Surg 17(5):685-688, 2008. 36. Tauber M, Karpik S, Matis N, et al: Shoulder arthroplasty for traumatic avascular necrosis. Clin Orthop Relat Res 465:208-214, 2007. 37. Warren RF, Ranawat CS, Inglis AE: Total shoulder replacement. Indications and results of the Neer nonconstrained prosthesis. In Inglis AE (ed): American Academy of Orthopedic Surgeons Symposium: Total Joint Replacement of the Upper Extremity. St. Louis, C V Mosby, 1982, p 56.

17

Chapter 31C Prosthetic Replacement for Nonunions and Malunions of the Proximal Humerus Samuel A. AntuÑa RaÚl Barco John W. Sperling Proximal humerus fractures are one of the most common upper extremity fractures seen by orthopedic surgeons. A small minority of these fractures treated with either open or closed treatment eventually develop into malunion or nonunion. Prevention is possible by early recognition of fracture displacement with proper serial radiographs and close clinical follow-up, including serial true anterior-posterior views and an axillary view of the shoulder. When malunion and nonunion develop, they are difficult to treat and represent one of the most challenging problems in shoulder surgery, with a high rate of complications. This chapter focuses on the indications, surgical technique, and results of replacement arthroplasty in these two fracture sequelae.

PROXIMAL HUMERUS NONUNIONS Nonunion of a fracture of the proximal humerus is uncommon. It is more frequently seen after failed treatment of displaced two-part surgical neck fractures and some three- and fourpart fractures.23 The diagnosis can be made as early as 3 months after the injury, when there is no evidence of radiographic bone healing. Several factors are associated with the formation of a surgical neck nonunion. Proximal humerus fractures are more prevalent among older patients with poor bone quality and 1

associated medical problems that create an unfavorable healing environment. There are multiple local anatomic factors that may hinder bone healing: distraction of the fracture fragments, soft-tissue interposition, or synovial fluid at the fracture site. Other factors associated with inadequate treatment can also be involved in the development of surgical neck nonunion: excessive distraction caused by hanging casts, overly early aggressive rehabilitation, and poor fixation of surgically treated fractures (Fig. 31C.1).

Classification of Nonunions of the Proximal Humerus Due to differences in outcomes depending on the location of the nonunion site, Checcia et al.9 proposed a classification system for nonunions of the proximal humerus. Nonunions of the surgical neck were divided into four groups. Group 1: High, two-part nonunion, includes fractures of the anatomical neck with a very small proximal fragment. Bone cavitation is seen at the proximal fragment due to rapid resorption of the cancellous bone under the humeral head.

2

FIGURE 31C.1 Radiograph of a patient with a proximal humerus nonunion after failed attempt to obtain union with ORIF. Severe resorbtion and cavitation of the humeral head can be noted.

Group 2: Low, two-part nonunion, includes nonunions occurring between the lesser tuberosity and the insertion of the pectoralis major tendon with a larger proximal fragment than in Group 1. Group 3: Complex nonunion, includes nonunions secondary to three-part, four-part, or head-splitting fractures of the surgical neck and with displacement of the tuberosities greater than 5 mm.

3

Group 4: Lost fragment nonunion, includes those after highenergy trauma, open fractures, and/or posttraumatic osteomyelitis of the proximal humerus. In their classification of sequelae of fractures of the proximal humerus, Boileau et al.7 included nonunions as type 3 when the greater tuberosity was still connected to the head fragment (corresponding to Checcia groups 1 and 2), and as type 4 when the tuberosity and the head are disconnected (corresponding to Checcia group 3). Both systems emphasize the importance of both the status of the greater tuberosity and the size and bone quality of the cephalic fragment. P.298

Treatment Options Patients who are minimally symptomatic with low functional demands may be treated nonoperatively. However, some patients present with significant pain and severe functional impairment. Open reduction and internal fixation with bone grafting results in an unsatisfactory clinical result in approximately 50% of patients.11 , 15 , 19 , 20 , 26 Slightly improved results have been obtained after fixation with a tension wire and an intramedullary nail,11 with the use of an intramedullary bone graft,28 or with a blade plate and autogenous graft.12 , 24 These techniques, however, are only applicable when there is good bone quality and no significant glenohumeral joint damage. When nonunion of the proximal humerus occurs in an elderly patient, it commonly presents with poor bone quality, severe resorption and cavitation of the humeral head, and

4

communication of the fracture with synovial fluid from the glenohumeral joint. All of these factors interfere with successful healing of the fracture. Additionally, internal fixation may not be feasible in the setting of a complex fracture of the proximal humerus or those fractures with a very small proximal fragment. In these two groups of patients, the most viable option is replacement of the humeral head.14 A third group of patients who may be candidates for a proximal humerus replacement are those who present after failed surgical reconstruction of the nonunion, in whom the bone quality has deteriorated to the point where no fixation method can be securely used.

Patient Evaluation Patients with nonunions of the proximal humerus present with pain of a variable degree and significant loss of function. Skin integrity should be checked in patients who had been treated surgically, and draining sinuses, denoting active infection, should be ruled out. A throughout neurologic examination should be performed, especially if the patient had a previous operation. The radiographic evaluation should include at least an AP view of the shoulder in the scapular plane and an axillary view. The status of the cephalic fragment, amount of bone loss at the nonunion site, presence of avascular necrosis of the humeral head, and involvement of the joint cartilage should be carefully evaluated when a shoulder replacement is being considered. A CT scan may be helpful in delineating a head-splitting component of the fracture and to evaluate the status of the greater tuberosity.

Surgical Technique

5

An extended deltopectoral incision is used. The dissection may be difficult in patients with previous open surgery due to soft-tissue retraction and anatomical distortion. If a wider exposure is necessary, an anteromedial approach may be utilized.27 The axillary nerve is palpated anteriorly under the inferior edge of the subscapularis and posteriorly as the nerve exists from the axilla near the humeral neck. The joint may be approached via an incision at the subscapularis insertion or by a lesser tuberosity osteotomy. Our preference is to preserve the lesser tuberosity in continuity with the medial calcar and greater tuberosity, if possible. Once the subscapularis is retracted medially, a complete capsulectomy is performed to help improve mobilization of the tuberosities. The nonunion site is identified and debrided by removal of any fibrous tissue or interposed soft tissue. If there is adequate bone stock in the humeral head, the greater tuberosity should not be osteotomized. In these shoulders, after the articular portion of the humeral head is excised with an oscillating saw, the humeral stem is skewered through the ring-shaped portion of bone containing the greater and lesser tuberosity passing through the nonunion site (Fig. 31C.2). If there is medial calcar erosion associated with the nonunion, a C-shaped fragment containing the greater and lesser tuberosity should be preserved, for later grafting of the medial calcar. If there is severe resorption of the humeral head, a small head fragment, or malunion of the greater tuberosity, an osteotomy may need to be performed with removal of the head fragment. The glenoid is evaluated for evidence of articular damage, and a glenoid component is implanted if significant chondral damage is present. An appropriately sized humeral trial stem

6

is placed and assessed for height and version using the surgical technique similar to that encountered in acute fractures. The final humeral component is definitively cemented according to the position of the previously placed trial stem. All cement at the nonunion site should be carefully removed and bone graft placed between the bone fragments. If there is a ring-shaped proximal fragment, cancellous chips from the humeral head are packed between the calcar and the shaft. If the medial calcar is deficient, a large corticocancellous bone graft from the head is wedged between the prosthetic head and the humeral shaft, according to the technique described by Lin et al.16 When a greater tuberosity osteotomy is performed, reconstruction follows the principles established for acute fractures.2 The tuberosities are always repaired to each other and to the shaft with nonabsorbable sutures incorporating the rotator cuff, and the subscapularis is reattached to the lesser tuberosity. Postoperatively, the arm is immobilized in a sling with the elbow at the site for 6 weeks. During this period, only gentle passive motion under supervision of a therapist is prescribed. Active motion is delayed until there is evidence of some bone healing on radiographs, usually at 6 weeks. Strengthening exercises are encouraged after 12 weeks.

Results The results of shoulder arthroplasty for the treatment of a proximal humerus nonunion are summarized in Table 31C.1. The average values for active elevation and external rotation are 93 degrees (range, 63-120) and 32 degrees (range 1554), respectively. Active elevation above the horizontal should not be routinely expected. Pain relief, however, is

7

more consistently achieved. The most common complication found in this group of patients is related to tuberosity healing problems. Better functional results have been reported when the proximal segment is preserved as a ring- or C-shaped fragment and the prostheses is inserted through the remaining humeral neck, with either cancellous bone graft placed at the nonunion site, or a large corticocancellous graft wedged medially substituting the absent calcar16 (Fig. 31C.3). The reverse shoulder arthroplasty has been successfully used in treatment of some fracture sequelae.6 , 29 Its role in the treatment of proximal humeral nonunions has not yet been clearly established. The reverse shoulder prosthesis may be a reasonable treatment option in the elderly patient with a proximal humeral nonunion when the greater tuberosity is disconnected from both the head fragment and the shaft, as in Bolileau's type 4 fracture sequelae.21 P.299

8

FIGURE 31C.2 A: Nonunion of the proximal humerus with varus displacement. B: After the articular portion of the humeral head is removed with an oscillating saw, a ring-shaped fragment including the greater tuberosity and medial calcar is preserved. The stem is skewed through both fragments, and cancellous bone graft is added to the nonunion site. C: When the medial calcar is deficient, a C-shaped segment is left after the articular portion is removed. Restoration of the humeral contour is achieved with a corticocancellous graft placed medially (1) which is sutured to the shaft and tuberosities (2). TABLE 31C.1 RESULTS OF SHOULDER ARTHROPLASTY FOR PROXIMAL HUMERUS NONUNIONS

9

No. case s

HA/TS A

Elevatio n

Ext . rot.

Pain relief

Norris et al.23

14

10/4

97

NA

100 %

Healy et al.15

6

6/0

72

30

100 %

Frich et al.13

7

Dines et al.10

6

NA

5/1

NA

NA

120

NA

41

100 %

NA

100 %

Norris et al.22

3

3/0

Nayak et al.19

7

7/0

110

20

85%

Durald e et al.11

10

9/1

86

37

NA

Boileau et al.7

6

6/0

63

26

80%

Antuña et al.2

25

21/4

88

38

95%

NA

10

Mansat et al.17

2

2/0

95

15

100 %

Lin et al.16

9

8/1

113

54

100 %

NA, Not available.

P.300

11

FIGURE 31C.3 A: Radiograph of a 63-year-old patient with a nonunion of the surgical neck. B: The implant was inserted through both fragments and cemented in the shaft. Heavy tension band sutures were used to control rotation between the fragments, and bone graft from the humeral head was added to the nonunion site. (From Antuna SA, Sperling JW: Prosthetic replacement for nonunions of proximal humerus fractures. In: Cofield RH, Sperling JW, eds. Revision and Complex Shoulder Arthroplasty. Philadelphia: Lippincott Williams & Wilkins; 259-265, 2010. With permission.)

PROXIMAL HUMERUS MALUNIONS Patients with proximal humerus malunions frequently present with pain and loss of function of the shoulder. Although some older patients are willing to accept functional limitations of shoulder elevation, many younger patients find this to be unacceptable. Proximal humerus malunions with adequate congruity of the glenohumeral joint have the potential to be satisfactorily managed with osteotomies to reposition the malunited segments. However, when there is joint incongruity secondary to a step-off of the intra-articular fracture fragments, osteonecrosis of the humeral head, or secondary degenerative joint disease, prosthetic arthroplasty should be considered.

Classification of Malunions of the Proximal Humerus A classification system for proximal humeral malunions proposed by Beredjiklian et al.4 includes three types: Type 1, malposition of the tuberosities; Type 2, incongruity of articular surface; and Type 3, articular fragment malposition. The authors emphasize that soft-tissue pathology plays a major role in the functional impairment and stiffness seen in proximal humeral malunions. Both the bone and soft-tissue

12

pathology need to be corrected at the time of surgery to optimize outcome. In Boileau's classification of fracture sequelae,7 malunions are included as type 1 when there is an impacted valgus or varus fracture with cephalic collapse or necrosis but a healed greater tuberosity (Fig. 31C.4). When there is severe distortion of the anatomy, with greater tuberosity malunion or nonunion, they are defined as type 4. This system has prognostic implications: type 1 deformities can be treated with standard shoulder arthroplasty without osteotomizing the greater tuberosity, while type 4 deformities require greater tuberosity osteotomy and repositioning, leading to a worse functional outcome.

Treatment Options Young active patients who have no radiographic and clinical evidence of degenerative changes on the joint surfaces may be candidates for an osteotomy. Significant improvements in forward elevation and pain relief have been reported after correctional osteotomy of proximal humeral malunions.3 , 8 , 25 In older, less active patients or when there is joint incongruity secondary to a step-off of the intra-articular fracture fragments, osteonecrosis of the humeral head, or secondary degenerative joint disease, prosthetic arthroplasty may be more appropriate and definitive.

Patient Evaluation Loss of mobility and pain are the main complaints in patients with symptomatic malunions. Differences between active and passive glenohumeral range of motion should be carefully evaluated. Loss of passive motion may indicate glenohumeral arthritis with or without capsular stiffness. The presence of a

13

pseudoparalytic shoulder indicates severe distortion of the tuberosity to shaft relationship. Preoperative imaging studies, including true AP and axillary radiographs of the shoulder, are essential. It may be beneficial to obtain radiographs of the contralateral shoulder for comparison of the patient's neck-shaft angle. Computed tomography (CT scans) with 3D reconstructions may be useful in complex cases.

Surgical Technique Arthroplasty for sequelae of proximal humeral fractures may be technically difficult, with soft-tissue abnormalities invariably present. The deltoid muscle and subscapularis may be atrophic in some cases. The subacromial, subdeltoid, and subcoracoid spaces are carefully freed of scar tissue. Contractures limiting elevation and rotation often require releases of the capsule from the humeral neck and the glenoid rim. P.301

The subscapularis is released from the scapular neck, and a Z-lengthening may need to be performed if external rotation is limited. Alternatively, a lesser tuberosity osteotomy with the subscapularis attached may be performed to improve mobilization.

14

FIGURE 31C.4 AP (A) and axillary (B) radiographs of a 68-year-old patient with a proximal humerus malunion after a three-part fracture. There is cephalic collapse with osteonecrosis and joint incongruity. The greater tuberosity is in continuity with the shaft.

Preparation of the humeral canal for placement of the prosthesis is performed. Management of greater tuberosity malposition is probably one of the most demanding steps of this procedure. Every effort is made to avoid performing the greater tuberosity osteotomy, including implantation of the humeral component in slight varus or valgus (Fig. 31C.5). Humeral components with a modified curvature of the stem or custom stems with short lengths can also be used to achieve good position of the prosthetic head on the osteotomized remaining humeral head, fitting the stem in the humeral canal and yet avoiding osteotomy of the greater tuberosity. If the tuberosity is osteotomized, great care should be taken to leave enough bone attached to the rotator cuff to allow 15

solid fixation of the tuberosities to the diaphysis. After the prosthesis is placed, the tuberosities are fixed to both the implant and the humeral shaft with heavy nonabsorbable sutures. Autologous bone graft may be taken from the humeral head or iliac crest to augment fixation.

Results The results of patients with old trauma are inferior to the results currently obtained in patients with primary osteoarthritis. Pain relief is more reliably achieved postoperatively than motion. Mansat et al.17 reported in 28 patients with sequelae of proximal humeral fractures treated with shoulder arthroplasty. Based on the Neer criteria, the results were satisfactory in only 64%. Mean active elevation was 107 degrees, and 85% of patients reported no or slight pain. The authors conclude that the malunion of the greater tuberosity can be tolerated if it does not compromise acceptable positioning of the humeral component. However, if an osteotomy needs to be performed due to major displacement, results are unpredictable.

16

FIGURE 31C.5 A: Proximal humerus malunion with varus deformity and secondary degenerative changes. B: A total shoulder replacement was implanted with the humeral component in slight varus to adapt to malunion and avoid greater tuberosity

17

osteotomy.

P.302

Antuña et al.1 and Beredjiklian et al.4 have reported similar results. Antuña et al.1 reported that 10 of 24 of their patients who had greater tuberosity osteotomy had a complication related to tuberosity nonunion, malunion, or resorption. Implantation of the humeral component in slight varus or valgus was not associated with an increased incidence of humeral component loosening. Beredjiklian et al.4 emphasized that malunion of the proximal humerus is often accompanied by some soft-tissue abnormality, such as softtissue contracture, a tear of the rotator cuff, or subacromial impingement, in addition to distortion of the bony anatomy. Both osseous and soft-tissue abnormalities need to be corrected at the time of surgery to improve the chances of a satisfactory result. Similarly, Boileau et al.5 reported 42% good to excellent results in 71 patients who underwent shoulder arthroplasty for sequelae of proximal humerus fractures. They reported a 27% complication rate. The most significant factor affecting results was the need for greater tuberosity osteotomy. All patients who underwent a greater tuberosity osteotomy were not able to regain active elevation above 90 degrees. In a recent report, Moineau and Boileau18 reviewed the results of 66 anatomic prosthesis in malunions with cephalic collapse or necrosis. Tuberosity osteotomy was not performed in any case. Mean active elevation was 140 degrees, and 91% of patients were satisfied. This group has reported better 18

functional results with a reverse prosthesis than with an anatomic implant in deformities with severe greater tuberosity malunion or nonunion (Boileau's type 4).6

SUMMARY Patients with significant pain and functional impairment secondary to a proximal humerus nonunion associated with osteoporosis, severe cavitation of the humeral head, and/or degeneration joint changes may benefit from a shoulder arthroplasty. Although function is not completely restored in most patients, high levels of subjective satisfaction and pain relief can be achieved. Better functional outcome may be expected when the proximal segment containing the greater and lesser tuberosities is preserved, and bone graft is used to reconstruct the deficient medial calcar. Replacement arthroplasty as treatment of a proximal humerus malunion is one of the most challenging procedures for a surgeon, with a relatively high rate of complications. Satisfactory long-term pain relief and good function can be achieved in approximately three of four cases. However, patients undergoing tuberosity osteotomy are at risk for obtaining a poorer result. Adequate exposure, proper correction of soft-tissue abnormalities, and preservation of the greater tuberosity or meticulous reattachment when osteotomy is performed seem to be of paramount importance for improving results and reducing complications.

References 1. Antuña SA, Sperling JW, Sanchez-Sotelo J, Cofield RH: Shoulder arthroplasty for proximal humeral malunions: longterm results. J Shoulder Elbow Surg 11:122-129, 2002.

19

2. Antuña SA, Sperling JW, Sanchez Sotelo J, et al: Shoulder arthroplasty for proximal humerus nonunions. J Shoulder Elbow Surg 11:114-121, 2002. 3. Benegas E, Zoppi Filho A, Ferreira Filho AA, et al: Surgical treatment of varus malunion of the proximal humerus with valgus osteotomy. J Shoulder Elbow Surg 16:55-59, 2007. 4. Beredjiklian PK, Iannotti JP, Norris TR, Williams GR: Operative treatment of malunion of a fracture of the proximal aspect of the humerus. J Bone Joint Surg 80:1484-1497, 1998. 5. Boileau P, Trojani C, Walch G, et al: Shoulder arthroplasty for the treatment of the sequelae of fractures of the proximal humerus. J Shoulder Elbow Surg 10:299-308, 2001. 6. Boileau P, Watkinson D, Hatzidakis AM, Hovorka I: Neer Award 2005: The Grammont reverse shoulder prosthesis: results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15: 527-540, 2006. 7. Boileau P, Walch G, Trojani C, et al: Classification and treatment for the sequelae of proximal humerus fractures: A prospective multicenter study of 71 cases. J Shoulder Elbow Surg 9:501, 1999. 8. Bronsard N, Boileau P: Conservative surgical treatment for surgical malunion of the proximal humerus. In Shoulder Concepts 2008. Proximal humeral fractures and fracture squelae. Montpellier, France, Sauramps Medcial, 2008, pp 249-252. 9. Checchia SL, Doneux P, Miyazaki AN, et al: Classification of non-unions of the proximal humerus. Int Orthop 24:217220, 2000. 10. Dines DM, Warren RF, Altchek DW, et al: Posttraumatic changes of the proximal humerus: malunion, nonunion, and

20

osteonecrosis. Treatment with modular hemiarthroplasty or total shoulder arthroplasty. J Shoulder Elbow Surg 2:11-21, 1993. 11. Duralde XA, Flatow EL, Pollock RG, et al: Operative treatment of nonunions of the surgical neck of the humerus. J Shoulder Elbow Surg 5: 169-180, 1996. 12. Dwyer AJ, Patnaik S, Smibert JG: Nonunion of complex proximal humerus fractures treated with locking plate. Injury Extra 38:409-413, 2007. 13. Frisch LH, Sojbjerg JO, Sneppen O: Shoulder arthroplasty in complex acute and chronic proximal humeral fractures. Orthopedics 9:949-954, 1991. 14. Galatz LM, Iannotti JP: Management of surgical neck nonunions. Ortho Clinics North Am 31:51-62, 2000. 15. Healy WL, Jupiter JP, Kristiansen TK, et al: Nonunion of the proximal humerus. A review of 25 cases. J Orthop Trauma 4:424-431, 1990. 16. Lin JS, Klepps SK, Miller S, et al: Effectiveness of replacement arthroplasty with calcar grafting and avoidance of greater tuberosity osteotomy for the treatment of surgical neck nonunions. J Shoulder Elbow Surg 15:12-18, 2006. 17. Mansat P, Guity MR, Bellumore Y, et al. Shoulder arthroplasty for late sequelae of proximal humeral fracture. J Shoulder Elbow Surg 13:12-18, 2004. 18. Moineau G, Boileau P: Post-traumatic cephalic collapse and necrosis (type 1-fracture sequelae): results of a nonconstrained anatomical prosthesis. In Shoulder Concepts 2008. Proximal humeral fractures and fracture squelae. Montpellier, France, Sauramps Medical, 2008, pp 193-208.

21

19. Nayak NK, Schickendantz MS, Regan WD, et al: Operative treatment of nonunion of surgical neck fractures of the humerus. Clin Orthop 313:200-205, 1995. 20. Neer CS II: Nonunion of the surgical neck of the humerus. Orthop Trans 7:389, 1983. 21. Neyton L, Garaud P, Boileau P: Results of reverse shoulder arthroplasty in proximal humerus fracture sequelae. In Reverse Shoulder Arthroplasty. Montpellier, France, Sauramps Medical, 2006, pp 81-101. 22. Norris T, Green A, McGuigan F: Late prosthetic shoulder arthroplasty for displaced proximal humerus fractures. J Shoulder Elbow Surg 4:271-280, 1995. 23. Norris TR, Turner JA, Bovill D: Nonunion of the upper humerus: An analysis of the etiology and treatment in 28 cases. In Post M, Morrey BF, Hawkins RJ, (eds): Surgery of the Shoulder. Chicago, IL, Mosby-Year Book, 1990, pp 63-67. 24. Ring D, McKee MD, Perey BH, Jupiter JB: The use of a blade plate and autogenous cancellous bone graft in the treatment of ununited fractures of the proximal humerus. J Shoulder Elbow Surg 10:501-507, 2001. 25. Russo R, Vernaglia Lombardi L, Giudice G, et al: Surgical treatment of sequelae of fractures of the proximal third of the humerus. The role of osteotomies. Chir Organi Mov 90:159169, 2005. 26. Scheck M. Surgical treatment of nonunions of the surgical neck of the humerus. Clin Orthop 167:255-259, 1982. 27. Tanner MW, Cofield RH: Prosthetic arthroplasty for fractures and fractures-dislocations of the proximal humerus. Clin Orthop 179:116-128, 1983. 28. Walch G, Badet R, Nové-Josserand I, et al: Nonunions of the surgical neck of the humerus: Surgical treatment with an

22

intramedullary bone peg, internal fixation, and cancellous bone grafting. J Shoulder Elbow Surg 5:161-168, 1996. 29. Wall B, Nove-Josserand L, O'Connor DP, et al: Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg Am 89:1476-1485, 2007.

23

Chapter 32 Shoulder Arthroplasty for Osteoarthritis Thomas W. Throckmorton John W. Sperling Robert H. Cofield

INTRODUCTION This chapter discusses shoulder arthroplasty for primary osteoarthritis, including the clinical features and surgical technique.16 , 18 , 19 Other chapters will focus on shoulder replacement for secondary osteoarthritis, posttraumatic arthritis, and osteonecrosis. In the early 1950s, Neer introduced the humeral head prosthesis with the intent to utilize this for complex shoulder fractures.49 , 52 In 1964, he tabulated the indications for humeral head replacement (HHR) to that point.50 These included 56 shoulders, and 42 procedures were done for acute or delayed trauma. In 1982, when Neer presented his classic series of patients undergoing total shoulder arthroplasty (TSA), the indications had changed.48 Rheumatoid arthritis, osteoarthritis, and posttraumatic arthritis were the most common diagnostic categories. In reporting our experience at the Mayo Clinic from 1975 to 1992, osteoarthritis, rheumatoid arthritis, and traumatic arthritis were again the three large diagnostic categories with revision surgery, osteonecrosis, and cuff-tear arthropathy representing the other three diagnostic groups with only a small miscellaneous group remaining.16 Table 32.1 depicts the diagnoses in shoulder arthroplasty for which surgery was performed between 1990 and 1999. It can be seen that 1

osteoarthritis now dominates the surgical indications with the other categories having lesser numbers. Revision surgery has become the second most common surgical indication with rheumatoid arthritis third, cuff-tear arthopathy fourth, acute trauma and traumatic-induced arthritis fifth, and osteonecrosis sixth. This distribution of indications remains largely unchanged over the past decade. TABLE 32.1 DIAGNOSES IN SHOULDER ARTHROPLASTY: 1990-1999

Total shoulder arthroplasty

Humeral head replacement

Total

Osteoarthritis

381

32

413

Rheumatoid arthritis

108

50

158

64

26

90

Cuff-tear arthropathy

37

77

114

Osteonecrosis

17

20

37

Revision surgery

140

37

177

Total

747

242

989

Trauma/traumatic arthritis

CLINICAL CHARACTERISTICS 2

The clinical features of primary osteoarthritis of the shoulder were originally defined by Neer, with understanding expanding with greater experience.48 , 51 This category of arthritis is the most predictable, with many patients having almost identical changes in the joint and the surrounding structures (Fig. 32.1). The humeral head exhibits a flattening and is seemingly enlarged with notable subchondral sclerosis. There may be subchondral cysts, but these are usually not prominent. The cartilage loss on the humeral head is superior and central, spreading toward the periphery. There are peripheral osteophytes, most prominent inferiorly, that contribute to the limitation of overhead movement typical of this disease pattern. On the glenoid, there may be cartilage loss over the entire surface, or it may involve just the posterior one half to two thirds of the surface. This is often associated with bony erosion. It can be central but is more commonly posterior, again associated with flattening of the joint surface. Cysts, when present, are usually posterior and are often not large but can complicate component implantation due the limited bone stock of the glenoid vault. Peripheral osteophytes surround the glenoid and, occasionally, are clearly visible during surgery. But more often they are hidden by the surrounding capsule.51 Joint position is often altered, with posterior humeral subluxation being the most common presentation.5 Curiously, this often simultaneously mimics superior subluxation on radiographs (Fig. 32.2). Alternatively, joint position is less commonly concentric with the humeral head sitting directly over the glenoid. Concurrent with subluxation of the glenohumeral joint are changes in the capsule, which is

3

usually enlarged posteriorly. When there are large osteophytes present, it may be enlarged inferiorly but typically has a contracture limiting forward elevation. The superior aspect of the capsule is usually unaltered, while the anterior aspect of the capsule is usually somewhat contracted. Loose bodies can be present. They P.304

can rest anteriorly in the subscapularis recess, posteriorly, inferiorly in the axillary recess, or they may develop synovial attachments.

FIGURE 32.1 Typical radiographic appearance of osteoarthritis.

4

FIGURE 32.2 Osteoarthritis associated with posterior humeral subluxation.

Tears of the rotator cuff in association with osteoarthritis are uncommon, although they do exist in 5% to 10% of patients.21 , 51 , 72 Usually, they are small to medium in size, involving the supraspinatus only or the supraspinatus and anterior aspect of the infraspinatus. Interestingly, since magnetic resonance imaging is now obtained on a number of shoulders, it is evident that there is often extensive degenerative change within the rotator cuff tendons in these patients in the absence of frank tendon tearing. The relationship of rotator cuff degeneration to primary shoulder osteoarthritis has yet to be clearly elucidated. However, it has been suggested that small nondisplaced or minimally retracted rotator cuff tears do not preclude a successful TSA.22

SURGICAL TECHNIQUE 5

The deltopectoral approach remains the utilitarian exposure for shoulder arthroplasty.48 Typically, there is a limited amount of scarring in the subacromial and subdeltoid regions. Upon incising the rotator interval, a large amount of clear, watery, synovial fluid may escape. If there is greater than 30 degrees of external rotation, the rotator cuff and capsular incision can be through the subscapularis tendon, leaving approximately 1 cm of tissue laterally to facilitate later repair. This incision is then continued inferiorly and somewhat laterally as the subscapularis attachment becomes more muscular. The antero-inferior capsule is then released from the humerus, and with increasing external rotation, the inferior aspect of the shoulder capsule is progressively brought into view. If osteophytes are present inferiorly on the humeral head, these are removed in order to see the capsule more fully. If forward elevation is restricted, as is usually the case, the inferior capsule is released from the humeral neck. The humeral canal is then prepared, using the humeral axis to reference the osteotomy. We prefer to use a cutting guide that employs both intramedullary and extramedullary referencing. The major extramedullary reference point is the axis of the forearm with the elbow flexed 90 degrees. The osteotomy is then indexed against the junction of the rotator cuff with the humeral head superiorly, cutting perhaps a millimeter above the junction to preserve the rotator cuff footprint. With the cutting guide set at 30 degrees, the posterior cuff attachment is rechecked to make sure that the osteotomy angle is correct. In shoulders without posterior humeral subluxation, posterior glenoid wear, or slightly more native glenoid retroversion, the angle of the cut may be increased to 35 degrees. Alternatively, if there is posterior

6

humeral subluxation and posterior glenoid wear, the angle of the cut may be decreased to approximately 20 degrees, thus altering the length of bone remaining on the posterior aspect of the humeral head and effectively tightening the posterior capsule and rotator cuff. Following humeral osteotomy, a humeral trial is placed and the humeral metaphysis is trimmed anteriorly, medially, and laterally so that there are no bony protrusions beyond the arc of the prosthesis. This avoids impingement later against the glenoid component. A trial reduction is then performed, and motion is assessed. If overhead motion is limited, the extent of inferior capsule release is reassessed and may be extended somewhat more posteriorly. If this is necessary, it is critical to release the capsule directly from bone to avoid injury to the axillary nerve. The humeral head trial is removed, and if an anterior contracture is present, an incision is made along the anterosuperior glenoid rim to release the capsular attachments. This incision then continues laterally along the superior band of the inferior glenohumeral ligament. The subscapularis and the attached segment of capsule can then be elevated from the subscapularis fossa to allow added flexibility to the anterior structures. Glenoid exposure is attained by abducting the humerus and placing a Fukuda retractor or humeral neck retractor across the front of the proximal humerus and behind the posterior lip of the glenoid. A long, bent knee retractor clears the anterior structures from the surgical field. Any soft tissue overhanging the rim of the glenoid is excised, revealing a clear view of the glenoid cavity. Care must be taken to obtain a direct, not an angled, view of the glenoid to ensure accurate preparation. If

7

there is any cartilage remaining on the anterior aspect of the glenoid, this is removed with a curette. This exposes the subchondral plate, which is used to compare with any areas of posterior wear. It is not unusual for the front quarter to one third of the glenoid to have this cartilage covering and to have a normal subchondral plate. Once removed, the central and posterior erosion becomes apparent. This erosion is of varying depth and involves the posterior two thirds to three quarters of the glenoid. When the erosion is small, reaming can proceed in the usual plane of the glenoid, as denoted by the remaining subchondral plate. If there is slightly more wear, the reamer is directed just a few degrees posteriorly to accommodate this small amount of wear and also to allow a firm seating of the glenoid component. If there is a larger amount of posterior wear, one can ream the glenoid normally or with only a slight posterior tilt if there is ample glenoid neck present to seat a component. Clavert and colleagues14 have provided some guidance with regard to the limits of asymmetric reaming. In a cadaveric study, they found that glenoid retroversion of more than 15 degrees cannot be reliably corrected to allow insertion of a glenoid component with peripheral pegs. If there is not, and only a small amount of anterior reaming is possible, then bone graft is added to the deficient area posteriorly after the glenoid has been prepared. Unfortunately, the potential alternative of using augmented glenoid components in this setting has been unsatisfying.56 Following satisfactory reaming of the glenoid, the vault is meticulously cleaned and the implant is then fixed in position. The rectractors are cleared from the glenoid. The humeral trial is removed, the component is fixed in position, and

8

various sizes of humeral heads are then trialed. Once the proper head size is selected, it is impacted into position and the joint is reduced for the final time (Fig. 32.3). The subscapularis and anterior shoulder capsule are carefully repaired. The shoulder is then taken through a range of motion, and the amount of external rotation, internal rotation, and elevation are recorded, as a guide to planning the physiotherapy in the early postoperative period. P.305

FIGURE 32.3 Postoperative radiograph following TSA with a modular system.

Patients are started on a supervised physiotherapy program in the hospital that emphasizes passive motion for the first 6 weeks. Thereafter, active-assisted and active motion are initiated for forward elevation and internal and external

9

rotation. Resistive activities are delayed, typically to 8 to 12 weeks postoperatively.

OUTCOMES Overview The average age of patients who undergo shoulder arthroplasty is the youngest among all major joint replacements.75 However, there are few reports on the longterm results of shoulder arthroplasty. Wirth and Rockwood noted in their review of the literature from 1975 to 1995 that the average length of follow-up in 41 reported series on shoulder arthroplasty was only 3.5 years.75 Moreover, of the 21 reports with a minimum follow-up of 2 years, only five had a mean follow-up of 5 years or more. The purpose of this chapter will be to review the results of hemiarthroplasty and unconstrained TSA for primary osteoarthritis. Encouraging outcomes have been reported with the use of HHR and TSA for the treatment of primary shoulder osteoarthritis. It is important to note that outcomes of TSA for primary osteoarthritis have continued to improve. Due to the more extensive capsule releases that are done, the great attention to bone work, the presence of adjunctive instruments to prepare the humerus and the glenoid, and the variation in implant sizes, one can now obtain stability of the joint in almost all patients and anticipate three-quarters normal active motion. Over the past decade, improved surgical technique and implant design have been the focus of investigation.

Humeral Head Replacement

10

Hemiarthroplasty of the shoulder has been available for over 40 years. Recently, the majority of reports concerning HHR are based on the results of trauma, which is discussed in a separate chapter. A number of investigators have used HHR for the reconstruction of shoulders afflicted by osteoarthritis (Fig. 32.4) The landmark article by Neer in 1974 demonstrated that good results could be obtained.51 In osteoarthritis, like osteonecrosis, the muscles about the shoulder are nearly normal and can achieve excellent return of movement and strength when a stable, relatively painless articulation is created.

FIGURE 32.4 Hemiarthroplasty for osteoarthritis of the shoulder.

There are various alternative designs of HHR, the results of which are presented in Table 32.2. In addition to standard unipolar hemiarthroplasty, other authors have reported

11

promising outcomes using a bipolar design for the treatment of primary osteoarthritis.3 In their study of 48 shoulders followed for an average of approximately 3 years, 92% of patients had good pain relief and 96% were subjectively improved. Further, 92% achieved satisfactory outcomes by objective criteria. The authors conclude that this design offers an acceptable alternative to standard shoulder arthroplasty at early follow-up. Steffee and Moore63 in North America and Jonsson and coworkers in Scandinavia37 , 38 employed a metallic cup to resurface the humeral head. The early results reported by Steffee and Moore were quite good, with pain relief very satisfactory and return of movement similar to that achieved with any style of HHR. Curiously, the return of active movement in the patients reported by Jonsson and co-workers was strikingly less than that reported by Steffee and Moore. These investigators reported almost no complications; however, evaluations of these patients were rather short term, and the type and frequency of complications of this particular design of HHR are not well established. A similar type of hemiarthroplasty that has been effective in treating shoulder osteoarthritis has been advanced by Copeland.40 By employing a resurfacing implant and cementless fixation, promising results were initially reported at 5 to 10 years of follow up for a variety of diagnoses including osteoarthritis. A subsequent study focusing purely on primary shoulder osteoarthritis found excellent results using both hemiarthroplasty and TSA designs. However, there were fewer revisions required in the hemiarthroplasty group, and the results were essentially equivalent. The authors advocate the use of their stemless hemiarthroplasty for the

12

treatment of shoulder osteoarthritis.41 Further, it has been shown that use of this implant can be used with minimal morbidity and an early rehabilitation program in elderly patients.47 A final variant of HHR that has been advanced is standard hemiarthroplasty combined with concentric glenoid reaming but without component implantation: the so-called “ream and run” technique. Proponents of this operation recommend reaming the glenoid to a diameter 2 mm greater than the implanted prosthetic humeral head to optimize the balance between P.306

glenohumeral conformity and stability. Using the Simple Shoulder Test as the primary measurement of functional outcome, an initial comparative study reported equal gains in patients undergoing TSA and the ream and run at 3 years of follow-up.15 Another more recent study reported patient selfassessed outcomes after undergoing the ream and run technique. Significant improvements in pain, range of motion, and functional outcome were reported at a mean follow-up of 2.7 years.43 There were no surgical complications or cases that required revision. Patients with a preserved joint space on follow-up radiographs had significantly better function than those where no joint space was visible. TABLE 32.2 RESULTS OF VARIOUS DESIGNS OF HHR FOR OSTEOARTHRITIS

13

Shoulder s

Pain relie f (%)

Active elevatio n (degree)

Design

Study

Standard

Zuckerman and Cofield77

85

83

120-135

Rispoli et al.57

51

55

134

Edwards et al.24

89

130

Sperling et al.61

78

117

Swanson et al.64

35

89

71

Arredondo and Worland3

48

92

123

14

86

101

108

90

51

82

147

26

100

57

HHR

Bipolar

Watson7 3

Worland and Arredondo76

Metal cup Steffee and Moore63

Jonsson et al.38

14

Jonsson et al.37

5

100

73

Resurfacin g Levy and Copeland40

30

124

Levy and Copeland41

41

133

Mullett et al.47

10

106

Ream and Run Lynch et al.43

38

86

138

Mayo Clinic Experience Zuckerman and Cofield77 reported on the results of 85 patients who underwent proximal humeral prosthetic replacement for glenohumeral arthritis, specifically osteoarthritis and rheumatoid arthritis. Follow-up greater than 2 years was available in 72 shoulders, with 36 shoulders in each diagnostic category. Satisfactory pain relief was obtained in 83% of the shoulders with osteoarthritis and in 89% of the shoulders with rheumatoid arthritis. In osteoarthritis, the return of motion was typically two-thirds to three-fourths normal and in rheumatoid arthritis one-half to two-thirds normal, depending on the severity of involvement of the surrounding soft tissues. Overall, while between 80% and 90% of patients achieved pain relief, at least one half of the remaining patients have either seriously considered or have undergone conversion of their HHR to TSA for pain relief. 15

Rispoli and colleagues57 recently updated our experience with this technique and found that hemiarthroplasty continues to provide significant improvements for patients with osteoarthritis but is still associated with a high rate of unsatisfactory outcomes and revision surgery. In this series, 51 shoulders were followed for an average of over 11 years (minimum 5 years). Hemiarthroplasty was associated with significant improvements in pain and range of motion. However, 16 shoulders reported moderate or severe pain at final follow-up and 10 had undergone revision procedures, primarily for the treatment of painful glenoid arthritis. Overall, there were 10 excellent, 20 satisfactory, and 21 unsatisfactory outcomes using Neer's criteria. Based on this experience, we have come to believe that proximal humeral prosthetic replacement can be a very successful procedure in patients with glenohumeral arthritis; however, the degree and consistency of pain relief are neither as great nor as predictable as in TSA. We would consider this procedure in a younger osteoarthritic patient who wished to be more active and who would accept the possibility of less complete relief for the benefit of fewer self-imposed restrictions. The operation is also occasionally used in the osteoarthritic patient with compromised glenoid bone volume.

Unconstrained Total Shoulder Arthroplasty The Neer type of unconstrained TSA has been the standard and as such is the implant against which others have been compared for the surgical treatment of primary osteoarthritis (Fig. 32.5). Other types of unconstrained total shoulder arthroplasties, in addition to the Neer design, are available,

16

some of which are listed in Table 32.3. The results of arthroplasty using these systems parallel the results of the Neer TSA. Pain relief is typically about 90%, and the return of active abduction approximates two thirds of normal in a mixed patient series. Additionally, the results of newer thirdgeneration implants such as the Tornier have been reported.24 , 45 , 71 These components have modularity of the stem, head, inclination, and offset. Interestingly, one study comparing the results of monoblock and modular TSA showed no significant differences between them.46 Additionally, the results of Churchill et al.13 suggest that humeral component modularity plays no significant role in outcomes. However, the long-term results of these new prostheses have yet to be determined. In the past decade, increasing attention has been directed toward the functional outcomes of TSA. Fehringer and coworkers25 reported postoperative function is directly related to the level of preoperative function. Further, they found that patients can expect to regain approximately two thirds of global shoulder function that was lacked preoperatively. Edwards et al.22 published their findings of a multicenter study regarding the influence of rotator cuff status on functional outcomes. P.307

They found that smaller cuff tears with minimal retraction did not significantly affect functional outcome. However, larger tears with fatty degeneration, particularly of the infraspinatus, correlated with a worse outcome. Of note, this study included patients undergoing both HHR and TSA. TABLE 32.3 RESULTS OF VARIOUS DESIGNS OF UNCONSTRAINED

17

TOTAL SHOULDER REPLACEMENT

Pai n reli ef %

Active abduc tion (degre es)

Study

Prosthesi s

Shoul ders

F/ U (y )

Gristi na et al.32

Monosph erical

100

3. 2

90

115

Amst utz et al.2

Dana

46

3. 5

91

120

Roper et al.58

RoperDay

25

5

10 0

78

Thom as et al.65

Dana

30

210

Brostr om et al.10

Dana St. Georg

26

3. 9

Figgie et al.27

Custom

27

5

Fenlin et al.n

Fenlin modular

47

4. 5

85

76

100

94

137

18

Garts man et al.31

Global

27

3

Cofiel d and Daly17

Cofield

32

4. 2

96

145

Sperli ng et al.60

Cofield

87

4. 6

87

138

Walch and Boilea u71

Tornier

86

2. 8

153

Edwar ds et al.24

Tornier

601

3. 7

145

37

4. 3

147

Orfaly et al.54

Global

128

F/U, follow-up.

Complications of TSA have also been studied. Perhaps most discussed of these is the issue of glenoid loosening. The radiographic analysis reveals that a substantial number of changes occur at the glenoid prosthesis-cement and cementbone interfaces. These are enumerated in Table 32.4 in regard to the Neer prosthesis. In the series in which the analysis includes a description of the location of the presence

19

of radiolucent zones, it can be seen that at least one third of shoulders have a radiolucent zone at the bone-cement interface, but in some series, up to two thirds of shoulders exhibit these changes. Some have noted a shift in glenoid component position in certain shoulders that might not otherwise have been seen without sequential radiographs. We have learned from total joint replacement in the hip and the knee that radiolucent zones do not necessarily imply that clinical failure is imminent. Radiolucent zones can be present on the initial postoperative radiograph, can develop later during the patient's course, and can progress in the extent and width. Progressive radiolucency is associated with the development of an increased area of fibrous or fibrous and histiocytic tissue, and, in some, revision surgery will be necessary because of pain or pain and bone destruction.

20

FIGURE 32.5 The Neer design of TSA.

Over the past decade, several studies have analyzed the rate of loosening following TSA. Cemented stems have an excellent track record, with a 2% rate of radiographic loosening.59 More recently, ingrowth humeral stems were found to have no evidence of loosening at an average followup of 51.5 months.67 With these encouraging results on the humeral side, the glenoid component continues to be a concern. Indeed radiographic loosening rates up to 63% have been reported28 (Fig. 32.6). However, one recent report found 10% of implants to be at risk for loosening at an

21

average follow-up of approximately 4 years.66 Interestingly, there was no difference between pegged and keeled designs regarding the rate of radiographic loosening. Another encouraging report has demonstrated a 10% rate of glenoid radiolucencies on initial postoperative films.8 The authors attribute these results to the use of a cement pressurization technique but note that longer-term follow-up is necessary to fully evaluate the ultimate outcome. Thus, the development of methods to improve the longevity of glenoid implants is an ongoing area of investigation. Another active area of current investigation involves determining the root causes of failure in TSA, particularly glenoid loosening. One study focused on the issue of humeral head malcentering as a component of the osteoarthritic process, which can therefore produce asymmetric stress on the glenoid with resultant failure.70 Implicit in this data is the goal of precise surgical technique to successfully restore native shoulder biomechanics. Some have advocated computer-assisted navigation to this end. Edwards et al.23 recently reported this technique to be highly accurate in an initial cohort. The authors conclude that longer-term studies are necessary to fully determine the utility of the concept. P.308

TABLE 32.4 ROENTGENOGRAPHIC ANALYSIS OF GLENOID COMPONENT OF NEER TOTAL SHOULDER REPLACEMENT

22

Radiolucent zones %

Should ers

Non e

An y are a

Neer et al.48

194

70

30

Bade et al.4

38

33

67

73

29

Wilde et al.74

38

7

Adams et al.1

33

36

Barrett et al.6

50

Kelly et al.39

40

Frich et al.29

50

Study

Ke el

Shift of compon ent %

71

33

11

93

68

26

74

36

17

83

63

Cofield 20

10

No data

23

Barrett et al.7

140

18

82

55

Brenne r et al.9

37

33

57

2

Hawki ns et al.34

70

Near ly all

McCoy et al.44

29

14

86

Vahva nen et al.69

41

68

32

Friedm an et al.30

24

42

Torchi a et al.68

89

12

2

88

Mayo Clinic Experience Over the last 20 years, there has been extensive experience at the Mayo Clinic with the use of the unconstrained TSA. In 1984, 73 Neer-type shoulder arthroplasties in 65 patients were evaluated at 2 to 6.5 years after operation.20 Pain relief was satisfactory in 92% of the shoulders. The return of active abduction averaged 141 degrees in osteoarthritis.

24

Postoperative external rotation averaged 48 degrees for the 73 shoulders. The amount of postoperative movement obtained was related to the original diagnosis, as noted above, and also to the extent of rotator cuff disease. Complications occurred in 13 patients, and included single instances of nerve injury, wound hematoma, and nonfatal pulmonary embolus. Additionally, reflex dystrophy developed in two patients, recurrent rotator cuff tearing in five, and, significantly, symptomatic glenoid loosening in three. Five reoperations were necessary: one to treat the wound hematoma, a second to deal with the nerve injury, and three to revise loosened glenoid components. These three latter revisions produced satisfactory outcomes for two of the patients. From this experience, we concluded that the operation was technically difficult, that particular attention must be paid to the status of the rotator cuff, and the postoperative rehabilitation program must maximize the potential for rotator cuff healing to maximize the potential return of movement and strength. Also, we learned that clinically significant component loosening was uncommon. But when it did develop, it occurred on the glenoid side and usually rather late. Implicit in this discussion is the realization that the results following unconstrained TSA are substantially better than the results obtained following the use of semiconstrained or constrained implants.

25

FIGURE 32.6 A loosened glenoid component following TSA. This radiograph was taken 62 months following the index procedure.

More recently, the long-term results of 113 total shoulder arthroplasties performed with a Neer prosthesis between 1975 and 1981 were reviewed.68 The indication for the surgery was moderate or severe pain in association with osteoarthritis, rheumatoid arthritis, and old fractures or dislocations with posttraumatic arthritis. Kaplan Meier analysis estimated the probability of implant survival to be 93% after 10 years and 87% after 15 years. Fourteen shoulders underwent revision surgery. Eighty-nine shoulders were available for follow-up at a minimum of 5 years from the time of shoulder arthroplasty (mean 12.2 y; range 5-17 y). There was acceptable pain relief in 83% of shoulders. There 26

was a mean improvement in active abduction of 40 degrees. The amount of abduction was related to the condition of the rotator cuff. Radiolucencies were seen around 75 glenoid components, and 39 (44%) of them had definite radiographic evidence of loosening. There was a correlation between glenoid loosening and pain. In regard to the humeral component, there was a shift in the humeral component position in 49% of the press-fit stems and in none of the cemented stems. However, there was association between radiographic humeral component loosening and pain. The most recent studies from our institution have continued to report satisfactory improvements in pain and range of P.309

motion but have also seen lower rates of radiographic loosening. As noted previously, we now rarely see radiolucencies around ingrowth stems and have seen a decrease in at-risk glenoid components to approximately 10% at 4 years of follow-up.66 , 67 We attribute these improved results to improvements in stem technology utilizing an ingrowth surface around the proximal one fourth of the prosthesis as well as careful attention to cement technique during glenoid preparation and obtaining optimal joint balance.

Humeral Head Replacement Versus Unconstrained Total Shoulder Arthroplasty In the past decade, increasing study has been directed toward comparing the outcomes of hemiarthroplasty to those

27

of TSA. Numerous studies investigating this issue have been advanced, and their results are summarized in Table 32.5. In general, the preponderance of evidence suggests an advantage of TSA over hemiarthroplasty for the surgical treatment of osteoarthritis. A systematic review of 1952 shoulder arthroplasties by Radnay et al.55 demonstrated significantly superior pain relief, range of motion, and satisfaction in patients undergoing TSA. The authors additionally note a significantly lower revision rate in the total shoulder group. Another large-scale meta-analysis found better functional outcomes in the total shoulder group at a minimum follow-up of 2 years.11

Mayo Clinic Experience We previously reviewed the long term results of Neer arthroplasty in patients 50 years old or younger.62 There were 74 hemiarthroplasties and 34 total shoulder arthroplasties followed for a minimum of 5 years (mean, 12.3 y) or until revision. Though there was significant improvement in pain and range of motion, there were no significant differences between the two procedures with respect to these variables. Survival estimates for the hemiarthroplasty were 92% at 5 years, 83% at 10 years, and 73% at 15 years. The estimated survival of the total shoulder prostheses was 97% at 5 years, 97% at 10 years, and 84% at 15 years. The data from the study indicated that a shoulder arthroplasty provides marked long-term relief of pain and improvement in motion. However, nearly half of all young patients who have a shoulder arthroplasty have an unsatisfactory result, according to a modified Neer result rating system.

28

TABLE 32.5 RESULTS OF HHR VERSUS THOSE OF TSA IN COMPARATIVE STUDIES

Study

No. of hemiarthropl asty

No. of TS A

Avera ge follow -up (mo)

Bryant et al.11

50

62

24

TSA

Better performa nce

Lo et al.42

21

20

24

No difference

Buchne r et al.12

22

22

12

TSA

33

95

46

TSA

28

37

51.6

TSA

Iannott i and Norris3 5

Orfaly et al.54

Norris and Iannott i53

43

133

46

No difference

Hains et al.33

42

82

61.2

No difference

29

Edwar ds et al.24

89

601

43.3

TSA

Gartsm an et al.31

24

27

35

TSA

4998

874 3

N/A

TSA

78

36

201.6

TSA

Jain et al.36

Sperlin g et al.61

We recently updated this series to include follow-up at a minimum of 15 years (average 16.8).61 With this more extensive follow-up, there were again no differences in pain relief or range of motion between the two groups, though both of them experienced significant improvements in these parameters. Radiographic evaluation revealed humeral prosthetic lucencies were more common following TSA (P = 0.0079). Radiolucent lines were present around 76% of glenoid components. Glenoid erosion was noted in 72% of hemiarthroplasties. There was a higher rate of excellent and satisfactory scores in the total shoulder group (52%) than the hemiarthroplasty cohort (40%). Kaplan-Meier analysis also demonstrated an advantage to total shoulder replacement. Total shoulder survival was estimated to be 97% at 10 years and 84% at 20 years. In contrast, hemiarthroplasty survival was 82% at 10 years and 75% at 20 years. Hemiarthroplasty

30

was, therefore, associated with a higher rate of failure and revision than total shoulder replacement. In reviewing this experience, we have learned that the clinical results of TSA continue to be excellent with this longer followup period. The frequency of complications and the need for revision are low. However, when revision surgery is needed, the most common reason is glenoid loosening. The radiographic analysis suggests that additional revisions may be necessary as the length of follow-up increases. We also recommend caution when either a hemiarthroplasty or a TSA is offered to patients who are 50 years old or less.

CONCLUSION In summary, this chapter has reviewed the history, clinical characteristics, and technique of shoulder arthroplasty for primary osteoarthritis. Outcomes continue to improve as implants and surgical technique evolve. Hemiarthroplasty of some type remains an acceptable alternative, primarily in those patients with limited glenoid bone stock, or in younger patients who wish to remain more active. In contrast, TSA has emerged as the superior option regarding pain relief, recovery of shoulder motion, and implant longevity. Studies with more extensive follow-up will undoubtedly give valuable perspective as experience with TSA for shoulder osteoarthritis continues to accrue. P.310

References

31

1. Adams MA, Weiland AJ, Moore JR: Nonconstrained total shoulder arthroplasty. An eight year experience. Orthop Trans 10:232, 1986. 2. Amstutz HC, Thomas BJ, Kabo JM, et al: The Dana total shoulder arthroplasty. J Bone Joint Surg 70A:1174-1182, 1988. 3. Arredondo J, Worland RL: Bipolar shoulder arthroplasty in patients with osteoarthritis: Short-term clinical results and evaluation of birotational head motion. J Shoulder Elbow Surg 8:425-429, 1999. 4. Bade HA, Warren RF, Ranawat C, Inglis AE: Long term results of Neer total shoulder arthroplasty. In Bateman JE, Welsh RP (eds): Surgery of the Shoulder. St. Louis, CV Mosby, 1984, p 249. 5. Badet R, Boulahia A, Walch G: Computerized tomography measurement of anteroposterior humeral dislocation. Proposing a method. Application to centered osteoarthritis. Rev de Chirurgie Orthopedique et Reparatrice de 1 Appareil Moteur 84:508, 1998. 6. Barrett WP, Franklin JL, Jackins SE, et al: Total shoulder arthroplasty. J Bone Joint Surg 69A:865-872, 1987. 7. Barrett WP, Thornhill TS, Thomas WH, et al: Nonconstrained total shoulder arthroplasty in patients with polyarticular rheumatoid arthritis. J Arthroplasty 4:91-96, 1989. 8. Barwood S, Setter KJ, Blaine TA, Bigliani LU: The incidence of early radiolucencies about a pegged glenoid component using cement pressurization. J Shoulder Elbow Surg 17(5):703-708, 2008.

32

9. Brenner BC, Ferlic DC, Clayton ML, Dennis DA: Survivorship of unconstrained total shoulder arthroplasty. J Bone Joint Surg 71A:1289-1296, 1989. 10. Brostrom LA, Kronberg M, Wallensten R: Should the glenoid be replaced in shoudler arthroplasty with an unconstrained Dana or St. Georg prosthesis? Ann Chir Gynaecol 81:54-57, 1992. 11. Bryant D, Litchfield R, Sandow M, et al: A comparison of pain, strength, range of motion, and functional outcomes after hemiarthroplasty and total shoulder arthroplasty in patients with osteoarthritis of the shoulder: A systematic review and meta-analysis. J Bone Joint Surg 87A(9):1947-1956, 2005. 12. Buchner M, Eschbach N, Loew M: Comparison of the short-term functional results after surface replacement and total shoulder arthroplasty for osteoarthritis of the shoulder: A matched-pair analysis. Arch Orthop Trauma Surg 128:347354, 2008. 13. Churchill RS, Kopjar B, Fehringer EV, et al: Humeral component modularity may not be an important factor in the outcome of shoulder arthroplasty for glenohumeral osteoarthritis. Am J Orthop 34(4):173-176, 2005. 14. Clavert P, Millett PJ, Warner JJ: Glenoid resurfacing: What are the limits to asymmetric reaming for posterior erosion. J Shoulder Elbow Surg 16(6):843-848, 2007. 15. Clinton J, Franta AK, Lenters TR, et al: Nonprosthetic glenoid arthroplasty with humeral hemiarthroplasty and total shoulder arthroplasty yield similar self-assessed outcomes in the management of comparable patients with glenohumeral arthritis. J Shoulder Elbow Surg 16(5):534-538, 2007.

33

16. Cofield RH, Becker DA: Shoulder arthroplasty. In Morrey BF (ed): Reconstructive Surgery of the Joints, 2nd ed. New York, Churchill Livingston, 1996, p 753. 17. Cofield RH, Daly PJ: Total shoulder arthroplasty with a tissue ingrowth component. J Shoulder Elbow Surg 1:77, 1992. 18. Cofield RH: Degenerative and arthritic problems of the glenohumeral joint. In Rockwood CA Jr, Matsen FA III (ed): The Shoulder. Philadelphia, WB Saunders, 1990, p 678. 19. Cofield RH: The shoulder. In Kelly WN, Haris ED Jr, Ruddy S, Sledge CB (eds): Textbook of Rheumatology, 5th ed. Philadelphia, WB Saunders, 1997, p 1696. 20. Cofield RH: Total shoulder arthroplasty with the Neer prosthesis. J Bone Joint Surg Am 66:899-906, 1984. 21. Cofield RH: Unconstrained total shoulder prostheses. Clin Orthop 173:97, 1983. 22. Edwards TB, Boulahia A, Kempf JF, et al: The influence of rotator cuff disease on the results of shoulder arthroplasty for primary osteoarthritis: results of a multicenter study J Bone Joint Surg-Am 84(12):2240-2248, 2002. 23. Edwards TB, Gartsman GM, O'Connor DP, Sarin VK: Safety and utility of computer-aided shoulder arthroplasty. J Shoulder Elbow Surg 17(3):503-508, 2008. 24. Edwards TB, Kadakia NR, Boulahia A, et al: A comparison of hemiarthroplasty and total shoulder arthroplasty in the treatment of primary glenohumeral osteoarthritis: Results of a multicenter study. J Shoulder Elbow Surg 12(3):207-213, 2003. 25. Fehringer EV, Kopjar B, Boorman RS, et al: Characterizing the functional improvement after total shoulder

34

arthroplasty for osteoarthritis. J Bone Joint Surg Am 84(8):1349-1353, 2002. 26. Fenlin JM Jr, Ramsey ML, Allardyce TJ, Frieman BG: Modular total shoulder replacement. Design rationale, indications, and results. Clin Orthop 307:37-46, 1994. 27. Figgie MP, Inglis AE, Figgie HE III, et al: Custom total shoulder arthroplasty in inflammatory arthritis. Preliminary results. J Arthroplasty 7:1-6, 1992. 28. Franta AK, Lenters TR, Mounce D, et al: The complex characteristics of 282 unsatisfactory shoulder arthroplasties. J Shoulder Elbow Surg 16(5): 555-562, 2007. 29. Frich LH, Moller BN, Sneppen O: Shoulder arthroplasty with the Neer Mark-II prosthesis. Arch Orthop Trauma Surg 107:110-113, 1988. 30. Friedman RJ, Thornhill TS, Thomas WH, Sledge CB: Nonconstrained total shoulder replacement in patients who have rheumatoid arthritis and class-IV function. J Bone Joint Surg 71A:494-498, 1989. 31. Gartsman GM, Roddey TS, Hammerman SM: Shoulder arthroplasty with and without resurfacing of the glenoid in patients who have osteoarthritis. J Bone Joint Surg 82A(1):26-34, 2000. 32. Gristina AG, Romano RL, Kammire GC, Webb LX: Total shoulder replacement. Orthop Clin North Am 18:445-453, 1987. 33. Hains JF, Trail IA, Nuttall D, Birch A, Barrow A: The results of arthroplasty in osteoarthritis of the shoulder. J Bone Joint Surg 88B(4):496-501, 2006. 34. Hawkins RJ, Bell RH, Jallay B: Total shoulder arthroplasty. Clin Orthop 242:188-194, 1989.

35

35. Iannotti JP, Norris TR: Influence of preoperative factors on outcome of shoulder arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg 85A(2):251-258, 2003. 36. Jain NB, Hocker S, Pietrobon R, et al: Total arthroplasty versus hemiarthroplasty for glenohumeral osteoarthritis: Role of provider volume. J Shoulder Elbow Surg 14(4):361-367, 2005. 37. Jonsson E, Brattstrom M, Lidgren L: Evaluation of the rheumatoid shoulder function after hemiarthroplasty and arthrodesis. Scand J Rheumatol 17:17-26, 1988. 38. Jonsson E, Egund N, Kelly I, et al: Cup arthroplasty of the rheumatoid shoulder. Acta Orthop Scand 57:542-546, 1986. 39. Kelly IG, Foster RS, Fisher WB: Neer total shoulder replacement in rheumatoid arthritis. J Bone Joint Surg 69B:723-726, 1987. 40. Levy O, Copeland SA: Cementless surface replacement arthroplasty of the shoulder. 5- to 10-year results with the Copeland mark-2 prosthesis. J Bone Joint Surg Br 83(2):213221, 2001. 41. Levy O, Copeland SA: Cementless surface replacement arthroplasty (Copeland CSRA) for osteoarthritis of the shoulder. J Shoulder Elbow Surg 13(3):266-271, 2004. 42. Lo IK, Litchfield RB, Griffin S, et al: Quality-of-life outcome following hemiarthroplasty or total shoulder arthroplasty in patients with osteoarthritis: A prospective, randomized trial. J Bone Joint Surg 87A(10):2178-2185, 2005. 43. Lynch JR, Franta AK, Montgomery WH Jr, et al: Selfassessed outcome at two to four years after shoulder hemiarthroplasty with concentric glenoid reaming. J Bone Joint Surg Am 89(6):1284-1292, 2007.

36

44. McCoy SR, Warren RF, Bade HA III, et al: Total shoulder arthroplasty in rheumatoid arthritis. J Arthroplasty 4:105-113, 1989. 45. Merolla F, Paladini P, Campi F, Porcellini G: Efficacy of anatomical prostheses in primary glenohumeral osteoarthritis. Chir Organi Mov 91(2):109-115, 2008. 46. Mileti J, Sperling JW, Cofield RH, et al: Monoblock and modular total shoulder arthroplasty for osteoarthritis. J Bone Joint Surg Br 87(4):496-500, 2005. 47. Mullett H, Levy O, Raj D, et al: Copeland surface replacement of the shoulder. Results of an hydroxyapatitecoated cementless implant in patients over 80 years of age. J Bone Joint Surg Br 89(11):1466-1469, 2007. 48. Neer CS II, Watson KC, Stanton FJ: Recent experience in total shoulder replacement. J Bone Joint Surg 64-A:319, 1982. 49. Neer CS II: Articular replacement for the humeral head. J Bone Joint Surg 37-A:215, 1955. 50. Neer CS II: Follow-up notes on articles previously published in the journal. Articular replacement for the humeral head. J Bone Joint Surg 46-A:1607, 1964. 51. Neer CS II: Replacement arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg 56-A:1, 1974. 52. Neer CS, Brown TH Jr, McLaughlin HL: Fracture of the neck of the humerus with dislocation of the head fragment. Am J Surg 85:252, 1953. 53. Norris TR, Iannotti JP: Functional outcome after shoulder arthroplasty for primary osteoarthritis: A multicenter study. J Shoulder Elbow Surg 11(2):130-135, 2002. 54. Orfaly RM, Rockwood CA Jr, Esenyel CZ, Wirth MA: A prospective functional outcome study of shoulder arthroplasty

37

with an intact rotator cuff. J Shoulder Elbow Surg 12(3):2314221, 2003. 55. Radnay CS, Setter KJ, Chambers L, et al: Total shoulder replacement compared with humeral head replacement for the treatment of primary glenohumeral osteoarthritis: A systematic review. J Shoulder Elbow Surg 16(4):396-402, 2007. 56. Rice RS, Sperling JW, Miletti J, et al: Augmented glenoid component for bone deficiency in shoulder arthroplasty. Clin Orthop Relat Res 466:579-583, 2008. 57. Rispoli DM, Sperling JW, Athwal GS, et al: Humeral head replacement for the treatment of osteoarthritis. J Bone Joint Surg Am 88(12):2637-2644, 2006. P.311

58. Roper BA, Paterson JM, Day WH: The Roper-Day total shoulder replacement. J Bone Joint Surg 72B:694-697, 1990. 59. Sanchez-Sotelo J, O'Driscoll SW, Torchia ME, et al: Radiographic assessment of cemented humeral components in shoulder arthroplasty. J Shoulder Elbow Surg 10(6):526531, 2001. 60. Sperling JW, Cofield RH, O'Driscoll SW, et al: Radiographic assessment of ingrowth total shoulder arthroplasty. J Shoulder Elbow Surg 9:507-513, 2000. 61. Sperling JW, Cofield RH, Rowland CM: Minimum fifteenyear follow-up of Neer hemiarthroplasty and total shoulder arthroplasty in patients aged fifty years or younger. J Shoulder Elbow Surg 13(6):604-613, 2004. 62. Sperling JW, Cofield RH, Rowland CM: Neer hemiarthroplasty and Neer total shoulder arthroplasty in

38

patients fifty years old or less. Long-term results [see comments]. J Bone Joint Surg Am 80:464-473, 1998. 63. Steffee AD, Moore RW: Hemi-resurfacing arthroplasty of the shoulder. Contemp Orthop 9:51, 1984. 64. Swanson AB, de Groot Swanson G, Sattel AB, et al: Bipolar implant shoulder arthroplasty. Long term results. Clin Orthop 249:227-247, 1989. 65. Thomas BJ, Amstutz HC, Cracchiolo A: Shoulder arthroplasty for rheumatoid arthritis. Clin Orthop 265:125-128, 1991. 66. Throckmorton TW, Zarkadas PC, Sperling JW, Cofield RH: Pegged versus keeled glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 2010 Feb. 9 [Epub ahead of print]. 67. Throckmorton TW, Zarkadas PC, Sperling JW, Cofield RH: Radiographic stability of ingrowth humeral stems in total shoulder arthroplasty. Clin Orthop Relat Res 2010 March 16 [Epub ahead of print]. 68. Torchia ME, Cofield RH, Settergren CR: Total shoulder arthroplasty with the Neer prosthesis: Long-term results. J Shoulder Elbow Surg 6:495-505, 1997. 69. Vahvanen V, Hamalainen M, Paavolainen P: The Neer II replacement for rheumatoid arthritis of the shoulder. Int Orthop 13:57-60, 1989. 70. Von Eisenhart-Rothe R, Muller-Gerbl M, Wiedemann E, et al: Functional malcentering of the humeral head and asymmetric long-term stress on the glenoid: Potential reasons for glenoid loosening in total shoulder arthroplasty. J Shoulder Elbow Surg 17(5):695-702, 2008.

39

71. Walch G, Boileau P: Prosthetic adaptability: A new concept for shoulder arthroplasty. J Shoulder Elbow Surg 8:443-451, 1999. 72. Walch G, Boulahia A, Boileau P, Kempf JF: Primary glenohumeral osteoarthritis: Clinical and radiographic classification. The Aequalis group. Acta Orthopaedica Belgica 2(64 Suppl):46, 1998. 73. Watson M: Bipolar salvage shoulder arthroplasty. Followup in 14 patients. J Bone Joint Surg 78B:124-127, 1996. 74. Wilde AH, Borden LS, Brems JJ: Experience with the Neer shoulder replacement. In Bateman JE, Welsh RP (eds): Surgery of the Shoulder. St. Louis, CV Mosby, 1984. 75. Wirth MA, Rockwood CA Jr: Complications of total shoulder-replacement arthroplasty. J Bone Joint Surg Am 78:603-616, 1996. 76. Worland RL, Arredondo J: Bipolar shoulder arthroplasty for painful conditions of the shoulder. J Arthroplasty 13:631617, 1998. 77. Zuckerman JD, Cofield RH. Proximal humerus prosthetic replacement in glenohumeral arthritis. Orthop Trans 10:231, 1986.

40

Chapter 33 Shoulder Arthroplasty In Rheumatoid Arthritis John W. Sperling

INTRODUCTION There has been a significant evolution in the treatment of patients with rheumatoid arthritis. In the past, one of the most common indications for shoulder arthroplasty was rheumatoid arthritis. Presently, improved medical management with newer pharmacologic agents has appeared to decrease the overall need for shoulder replacement surgery in this patient population. One of the central components in taking care of these patients is careful coordination of treatment with the patient's rheumatologist to effectively manage these medications in the perioperative period and maximize the patient's medical condition prior to surgery. Shoulder arthroplasty in a patient with rheumatoid arthritis presents a unique challenge for the surgeon. In addition to the typical cartilage loss and bone wear seen with osteoarthritis, a majority of patients with rheumatoid disease have some extent of soft tissue compromise. The influence of rotator cuff disease on the results of shoulder arthroplasty in patients with rheumatoid arthritis has varied significantly in the literature.5 , 10 The choice on the particular type of arthroplasty to use in patients with rheumatoid arthritis is a controversial decision.1 , 2 , 4 , 5 , 8 , 11 , 12 , 14 , 15

PATIENT EVALUATION History and Examination

1

One of the central components of the patient evaluation is obtaining a detailed history. It is essential to understand the severity of the patient's pain and functional limitations. One must also determine their ability to comply with postoperative restrictions and participate effectively in physical therapy. One needs to determine how long the patient has had rheumatoid arthritis and what nonoperative treatment modalities have been tried including medication, physical therapy, and injections. Many patients with rheumatoid arthritis have involvement with multiple joints. It is important to understand which joints are involved and develop a plan for the order that surgery should be performed. The examination of the patient begins with inspection. One should look for evidence of muscle atrophy as well as joint swelling. Careful examination of the cervical spine should be performed in these patients. There is a considerable incidence of cervical spine disease in these patients. In addition, cervical instability may be present. It is recommended that flexion and extension views of the neck be obtained prior to shoulder surgery to evaluate for cervical subluxation.9 Both active and passive range of motion of the shoulder are assessed including abduction, external rotation, and internal rotation. The majority of patients with severe shoulder arthritis have pain at the end range of motion associated with crepitus. It is essential to note whether there is a component of escape with attempted elevation. This is a sign of significant compromise of the coracoacromial arch and rotator cuff. Strength of the shoulder is tested in flexion, abduction, external rotation, and internal rotation. The posterior, lateral, and anterior portions of the deltoid are evaluated. Particularly

2

in patients who have undergone prior surgery, one must carefully ensure that the deltoid is intact.

Radiographic Studies There are four standard radiographic views obtained: 40degree posterior oblique views with internal and external rotation, a lateral scapula view, and an axillary view. The superior-inferior and medial-lateral acromiohumeral distance are evaluated. One can measure from the highest portion of the humeral head to the midportion of the acromion to evaluate the superior-inferior acromial-humeral distance. Less than 6 mm of acromiohumeral distance is associated with rotator cuff tearing.3 , 7 In regard to the medial-lateral acromiohumeral distance, usually the greater tuberosity is 1 to 2 cm lateral to the edge of the acromion on an anteroposterior (AP) view. If the greater tuberosity is in line or medial to the edge of the acromion, it implies significant glenoid wear (Fig. 33.1). There are a variety of advanced imaging modalities that can be performed. Determining the specific pattern and degree of glenoid wear is best done with a CT scan (Fig. 33.2). A threedimensional CT scan is very helpful in the setting of prior trauma and allows a more complete understanding of complex glenohumeral anatomy. Magnetic resonance image (MRI) or ultrasound can be used to assess the soft tissue including the rotator cuff and biceps tendon. In the setting of rheumatoid arthritis, MRI has the capacity to evaluate the degree of synovitis and associated cartilage wear. Ultrasound is portable, less expensive, and has the ability to be done in a dynamic manner. Some of the limitations include the

3

operator-dependent quality of images and a decreased ability to evaluate joint surfaces. P.313

FIGURE 33.1 A, B: Radiographs demonstrate severe glenohumeral arthritis. The greater tuberosity is in line with the lateral border of the acromion on the AP view indicating significant glenoid wear. On the axillary view, one can see the typical central wear pattern seen in rheumatoid arthritis.

4

FIGURE 33.2 A, B: CT scan views of a patient with severe glenoid erosion in the setting of rheumatoid arthritis.

SURGICAL TECHNIQUE Proper patient positioning is an important first step in the operative procedure. Great care needs to be taken in carefully positioning the patients' head and neck. Typically, a deltopectoral approach is used for exposure. Often, there is a triangle of fat present proximally between the pectoralis major and deltoid, just inferior to the clavicle. One of the distinctive characteristics of rheumatoid arthritis is the effect on the soft tissues. Accordingly, the deltoid can be particularly thin in patients with rheumatoid arthritis and great care should be taken to avoid tearing the muscle. In addition, considerable stiffness from contracture and scar tissue formation may be present in these patients. It is important to avoid vigorous external rotation of the arm, which could result in fracture.

5

In patients with significant stiffness and a frail deltoid, one may consider using anteromedial approach.6 This approach can be very useful in patients with a thin deltoid, severe scarring, bony deformity, or rotator cuff tearing requiring repair. The anterior deltoid is carefully incised off the superior aspect of the clavicle and acromion, allowing for exposure with minimum risk of tearing the anterior deltoid with retractors. At the end of the procedure, one meticulously repairs the deltoid back to its origin with multiple stitches. Gill and Cofield reported on the outcome of 81 patients who underwent this approach. There were no anterior deltoid detachments, and deltoid strength was preserved in all patients. P.314

Humeral component preparation and placement are not unlike that for other patients with shoulder arthritis. Nevertheless, the quality of the bone in patients with rheumatoid arthritis may be significantly compromised. An ingrowth humeral component may be used in patients with satisfactory bone quality. However, in patients with insufficient bone quality in the humerus, one may need to use cement fixation. In addition, one needs to be careful not to crush the proximal humerus with retractors during preparation of the glenoid. Usually, the humeral component is placed in 30 degrees of retroversion. It is important that the head face directly across from the glenoid with the arm in the neutral position. The rotator cuff needs to be carefully evaluated. If a tear is present and is amenable to repair, it is technically easier to place stitches through the tuberosity prior to seating the real

6

humeral component. The reparability of the rotator tear is the primary factor in determining whether or not to place a glenoid component.10 In general, among patients with an intact or repairable rotator tear, a glenoid component is placed if there is adequate glenoid bone stock present. However, in those patients with a nonrepairable rotator cuff tear, hemiarthroplasty or reverse arthroplasty is performed. A CT scan is extremely helpful in determining the amount of bone loss present, the specific wear pattern, the center point within the glenoid, as well as the glenoid version. In osteoarthritis, the typical wear pattern is posterior, whereas in rheumatoid arthritis it is central. It is helpful to use a small drill bit to verify the depth of the remaining glenoid. In general terms, a minimum of 12 mm of bone is needed to place a glenoid component. The evolution of modular humeral head components with eccentric and offset options has facilitated soft tissue balancing. Typically, 50% posterior and anteriorly translation of the humeral head across from the glenoid is desired with a spontaneous reduction when the pressure is released. The goal is to obtain passive elevation to approximately 160 degrees, internal rotation to 90 degrees, and external rotation to 50 degrees. A careful and meticulous repair of the subscapularis and rotator interval is performed to avoid instability.

7

FIGURE 33.3 A: AP radiograph of a patient with rheumatoid arthritis and severe pain. At the time of surgery, the rotator cuff was noted to be thin but intact. B: Radiograph taken 13 years following total shoulder arthroplasty. (From Sperling JW, Cofield RH, Schleck C: Total shoulder arthroplasty versus hemiarthroplasty for rheumatoid arthritis: Results of 303 consecutive cases. J Shoulder Elbow Surg 16:683-690, 2007.)

OUTCOME Hemiarthroplasty and total shoulder arthroplasty have both been shown to produce significant pain relief.12 , 13 Due to the often fragile nature of the soft tissue and bone, concerns remain concerning the durability of shoulder arthroplasty in this population. The literature has confirmed that patients with rheumatoid arthritis frequently demonstrate thinning or tearing of the rotator cuff.10 , 12 A concern in these patients is that progressive rotator cuff attenuation may occur with associated superior subluxation of the humeral head. This may lead to eccentric loading of the glenoid and subsequent glenoid component loosening. Consequently, some authors 8

have suggested that glenoid replacement in patients with rheumatoid arthritis be avoided due to concerns about rotator cuff degeneration and ensuing glenoid loosening.11

CURRENT PRACTICE In our practice, glenoid resurfacing is undertaken in patients with an intact or repairable rotator cuff and adequate glenoid bone stock. Results in the literature have demonstrated significantly better relief of pain and motion with TSA compared to hemiarthroplasty in patients with rheumatoid patients and an intact rotator cuff.13 Additionally, patients with an intact rotator cuff have a lower risk of requiring revision surgery. The most frequent reason for revision among hemiarthroplasties was painful glenoid arthritis (Fig. 33.3). In addition, the rate of symptomatic glenoid component loosening requiring revision surgery was less than that for painful glenoid arthritis. Sperling and Cofield also identified a high rate of intraoperative humerus fracture during arthroplasty for rheumatoid arthritis.13 It is important to be aware of this risk and avoid forceful manipulation of the shoulder. Among patients with poor quality bone, one may consider cement fixation of the humeral component.5 , 11 , 13 P.315

CONCLUSION Shoulder arthroplasty is an effective procedure to relieve pain and improve function in patients with rheumatoid arthritis. Among patients with an intact rotator cuff, TSA is the preferred procedure for pain relief, improvement in abduction,

9

and a lower risk of revision surgery. One should be aware that patients with rheumatoid arthritis are at higher risk of intraoperative fracture. Additional research will be necessary to determine the role of the reverse shoulder arthroplasty in patients with rheumatoid arthritis and irreparable rotator cuff tears.

References 1. Crossan JF. Vallance R: Clinical and radiological features of the shoulder joint in rheumatoid arthritis. J Bone Joint Surg 62B:116, 1980. 2. Crossan JF, Vallance R: The shoulder joint in rheumatoid arthritis. In Bayley I, Keddel L (eds.): Shoulder Surgery. New York, Springer-Verlag, 1982, pp 131-139. 3. Cruess RL: Rheumatoid arthritis of the shoulder. Orthop Clin N Am 11:333-342, 1980. 4. Fink B, Singer J, Lamla U, Ruther W: Surface replacement of the humeral head in rheumatoid arthritis. Arch Orthop Trauma Surg 124:366-373, 2004. 5. Friedman RJ, Thornhill TS, Thomas WH, Sledge CB: Nonconstrained total shoulder replacement in patients who have rheumatoid arthritis and class IV function. J Bone Joint Surg 71A:494-498, 1989. 6. Gill DR, Cofield RH, Rowland C: The anteromedial approach for shoulder arthroplasty: The importance of the anterior deltoid. J Shoulder Elbow Surg 13(5):532-537, 2004. 7. Lehtinen JT, Belt EA, Lyback CO, et al: Subacromial space in the rheumatoid shoulder: A radiographic 15-year follow-up study of 148 shoulders. J Shoulder Elbow Surg 9:183-187, 2000.

10

8. Levy O, Funk L, Sforza G, Copeland SA: Copeland surface replacement arthroplasty of the shoulder in rheumatoid arthritis. J Bone Joint Surg 86A:512-518, 2004. 9. Neva MH, Hakkinen A, Makinen H, et al: High prevalence of asymptomatic cervical spine subluxations in patients with rheumatoid arthritis waiting for orthopaedic surgery. Ann Rheum Dis 65(7):884-888, 2006. 10. Rozing PM, Brand R: Rotator cuff repair during shoulder arthroplasty in rheumatoid arthritis. J Arthroplasty 13:311319, 1998. 11. Sneppen O, Fruensgaard S, Johannsen HV, et al: Total shoulder replacement in rheumatoid arthritis: Proximal migration and loosening. J Shoulder Elbow Surg 5:47-52, 1996. 12. Sojberg JO, Frich LH, Johannsen HV, Sneppen O. Late results of total shoulder replacement in patients with rheumatoid arthritis. Clin Orthop 366:39-45, 1999. 13. Sperling JW, Cofield RH, Schleck C: Total shoulder arthroplasty versus hemiarthroplasty for rheumatoid arthritis: Results of 303 consecutive cases. J Shoulder Elbow Surg 16(2):e57-e58, 2007. 14. Stewart MPM, Kelly IG: Total shoulder replacement in rheumatoid disease: 7 to 13 year follow-up of 37 joints. J Bone Joint Surg 79B:68-72, 1997. 15. Trail IA, Nuttall D: The results of shoulder arthroplasty in patients with rheumatoid arthritis. J Bone Joint Surg 84B:1121-1125, 2002.

11

Chapter 34 Rotator Cuff Tear Arthropathy Joaquin Sanchez-Sotelo Cuff-tear arthropathy (CTA) was first described in detail by Neer23 in 1983 as a clinical entity consisting of severe disorganization of the glenohumeral joint following some massive tears of the rotator cuff. Two years before, McCarthy and coworkers had reported similar pathologic changes under the term “Milwaukee shoulder,”16 , 20 , 22 and had hypothesized that the bone and soft tissue destruction resulted from the production of basic calcium phosphate crystals and the associated release of proteases into the joint, as occurs in other crystalinduced arthritides. CTA and the Milwaukee shoulder are possibly a single pathologic entity whose etiology has not been completely elucidated. Recent investigations have demonstrated increased levels of apatite crystals, prostaglandin E, and matrix metalloproteinases in the synovial fluid of patients with full-thickness cuff tears.1 In addition, CTA seems to be associated with variants of two genes (ANKH and TNAP) implicated in extracellular inorganic pyrophosphate concentrations.24 CTA may tend to develop in patients with massive cuff tears and a genetic predisposition to primary crystal deposition. CTA should be distinguished from other conditions that may combine degenerative changes of the glenohumeral joint and a tear of the rotator cuff. The diagnosis of CTA requires the association of a massive and irreparable rotator cuff tear and glenohumeral cartilage loss. Progressive bone loss of the

1

humeral head, glenoid, coracoacromial arch, and/or distal clavicle is usually present as well.

CLINICAL PRESENTATION Patients with CTA are typically elderly and present with a history of long-standing shoulder pain, decreased active motion, and limited function.10 , 23 , 29 Some complain of recurrent episodes of shoulder swelling.23 , 32 They have commonly received multiple corticosteroid injections and may have undergone one or more operations, most frequently acromioplasty and rotator cuff debridement or repair.2 , 12 , 18 , 25 , 32 , 33 Physical examination usually reveals swelling of the shoulder in the subacromial and glenohumeral regions and atrophy in the supraspinous and infraspinous fossae. Glenohumeral motion may be accompanied by crepitus and is usually painful. Active and passive ranges of motion are decreased, and there is weakness, especially in abduction and external rotation. Many patients present with no active glenohumeral elevation, so-called pseudoparesis.31 The status of the deltoid muscle should be evaluated, especially in patients with a history of prior surgery. Deltoid weakness may severely compromise the function of shoulder arthroplasty. Anterosuperior glenohumeral instability is also common in severely affected shoulders or those with failed previous surgery. The radiographic findings in CTA are characteristic (Fig. 34.1). In addition to the glenohumeral joint space narrowing present in other forms of shoulder arthritis, the humeral head migrates superiorly and may contact the coracoacromial arch. There are variable degrees of bone loss secondary to erosion

2

of the acromion, distal clavicle, glenoid and coracoid process. The humeral head may collapse, and the inferior rim of the glenoid may create a humeral notch medially. CTA should be distinguished from inflammatory arthritis, infections, old posttraumatic arthritis, avascular necrosis, metabolic diseases, and neuropathic arthropathy.23 If alternative diagnoses can be excluded, no further laboratory or imaging studies are necessary. However, oftentimes patients will present with an MRI showing massive tearing of the rotator cuff with severe muscle atrophy and all the additional findings already described for radiographs.

TREATMENT OPTIONS When conservative treatment fails to control patient symptoms, several surgical options have been proposed. Arthroscopic debridement21 and biceps tenotomy4 may improve some P.317

patients temporarily. Glenohumeral arthrodesis may be considered for patients who have a nonfunctional deltoid muscle.3 Anatomic total shoulder arthroplasty is believed to be associated with a high rate of glenoid failure in the absence of a functional cuff.15 Shoulder hemiarthroplasty was the standard of care for CTA until recently.18 , 25 , 33 However, reverse shoulder arthroplasty has gained increasing popularity for the treatment of this condition (see chapter on Reverse total shoulder arthroplasty).7 , 9 , 13 , 27 , 28 , 31 Currently, we believe there is a role for both hemiarthroplasty and reverse total shoulder arthroplasty in the treatment of patients with end-stage CTA.

3

FIGURE 34.1 Anteroposterior radiograph showing the typical findings of CTA.

REVERSE TOTAL SHOULDER ARTHROPLASTY IN CTA Indications Reverse total shoulder arthroplasty provides a better chance of pain relief and functional improvement than shoulder hemiarthroplasty for most patients with CTA.7 , 9 , 13 , 27 , 28 , 31 It is currently the treatment option recommended to most of our patients presenting with this condition. Hemiarthroplasty is favored over reverse arthroplasty only when the remaining 4

glenoid bone stock does not allow secure implantation of the glenoid component. Some surgeons also consider hemiarthroplasty in patients with painful end-stage CTA but relatively well-preserved range of motion, especially in younger patients. Painful pseudoparesis, on the other hand, has a very low chance of improvement with hemiarthroplasty, especially in the presence of anterosuperior escape.

Technical Aspects The general principles of reverse arthroplasty design and technique are described elsewhere in this text. CTA usually represents a relatively straightforward condition for implantation of a reverse prosthesis. We prefer to perform the procedure through a deltopectoral approach. Any subscapularis tendon present is released and repaired at the end of the procedure. Reverse shoulder arthroplasty provides limited improvements in active external rotation, especially in patients with either complete disruption or severe atrophy of both the infraspinatus and the teres minor.26 Latissimus dorsi transfer with or without teres major transfer has been recommended as an adjunct procedure to improve the functional results of reverse arthroplasty.5 , 6 , 11 These two tendons may be transferred around the humeral diaphysis at the time of arthroplasty through the same deltopectoral approach (Fig. 34.2). Biomechanical studies have demonstrated the ability of latissimus dorsi transfer to improve active external rotation when combined with a reverse prosthesis.11 The external rotation moment arm seems to be larger when the latissimus tendon is attached to the posterior aspect of the greater tuberosity (adjacent to the teres minor insertion).

5

The results of this combined procedure have been reported in two separate studies. Gerber et al.17 reported on 10 patients who underwent a reverse prosthesis combined with latissimus dorsi transfer. Forward flexion improved from 94 to 139 degrees, but the gain in external rotation was only from 12 to 19 degrees, not significant. On the contrary, Boileau et al.5 have reported restoration of both active elevation and external rotation in 11 consecutive patients who underwent reverse arthroplasty and a combined latissimus dorsi/teres major tendon transfer for CTA with pseudoparalysis. Mean active elevation improved from 70 to 148 degrees, and mean active external rotation improved from -18 degrees to +18 degrees.

6

FIGURE 34.2 A: The latissimus dorsi and teres mayor tendons may be transferred

7

through the deltopectoral approach at the time of reverse shoulder arthroplasty. B: Note the transferred tendons (black arrow) after implantation of the prosthesis.

There is very little information to guide rehabilitation of the shoulder after reverse arthroplasty.8 We believe that early passive and active-assisted motions are safe, and favor letting patients to progress in their rehabilitation relatively quickly. In my current practice, I recommend use of a shoulder immobilizer for 2 to 3 weeks, active-assisted range of motion exercises for the first 6 to 8 weeks, and strengthening starting at 6 weeks and concentrating mostly on the deltoid. More protection is recommended when the initial fixation of the glenoid component is suboptimal or there are concerns about instability. P.318

Outcome The outcome of reverse total shoulder arthroplasty in patients with CTA is somewhat difficult to analyze. This is due on part to the various designs and indications included in each study. Table 34.1 summarizes the outcome reported using reverse arthroplasty in patients with CTA. We will review in detail the results of the larger series. The first modern study regarding the outcome of reverse arthroplasty for CTA using the Delta III implant was published by Sirveaux et al.27 in 2004. These authors reported on 80 patients with a mean follow-up of 3.7 years. The procedure was associated with good pain relief in 96% of the patients, mean active elevation increased from 73 to 138 degrees, and Constant scores improved from 22 to 65 points (Fig. 34.3). 8

There were five cases of aseptic loosening and seven of glenoid dissociation, and three implants were revised. The integrity of teres minor was found to be essential for recovery of external rotation and was associated with better Constant scores. Slightly worse results were reported by Werner et al.31 also using the Delta III implant. These authors reported on 58 consecutive shoulders followed for 3 years. Seventeen procedures were the primary treatment for the shoulder, and 41 were revisions after failed cuff repair or arthroplasty. Relative Constant scores (corrected for age and gender) improved from 29% to 64% and active elevation improved from 42 to 100 degrees, but there was an overall complication rate of 50% and an overall reoperation rate of 33%. Complications included infection (6 shoulders), dislocation (5 shoulders), mechanical failure (5 shoulders), acromial fracture (4 shoulders), and nerve dysfunction (1 shoulder). Results were noted to be worse in the revision setting. TABLE 34.1 OUTCOME OF REVERSE TOTAL SHOULDER ARTHROPLASTY IN CTA

9

F a i l e d

C T A o r m a s s i v e c u f f S t u d y

S i r v

t e a r

8 0

a r t h r o p l a s t y o r o t h e r d i a g n o s i s

-

M e a n F / U

P a i n

( y )

r e l i e f

3 . 7

9 6 %

E l e v a t i o n / f l e x i o n

1 3 8 d

S u b j e c t i v e

E R

1 1 d

s a t i s f a c t i o n

9 2 %

C o m p l i c a t i o n s

C o m m e n t s

G l e n

I m p o

10

e a u x 2 7

e g r e e

e g r e e

o i d l o o s e n i n g ( 5 ) G l e n o i d d i s s o c i a t i o n ( 7 )

r t a n c e o f t e r e s m i n o r f o r a c t i v e e x t e r n a l r o t a t i o n

11

n o t e d

W e r n e r 3 1

3 7

2 1

3 . 2

M e a n C o n s t a n t p a i n s c o r e 1 0 . 5

1 0 0 d e g r e e

1 2 d e g r e e

N R

C o m p l i c a t i o n r a t e 5 0 % , r e o p e r a t i o n r a t

M o r e r e o p e r a t i o n s i n r e v i s i o n s u r g e r y

12

e 3 3 %

F r a n k l e 1

6 0

-

2 . 7

M e a n V A S

4

s c o r e 2 . 2

1 0 5 d e g r e e

4 1 d e g r e e

9 5 %

C o m p l i c a t i o n r a t e 1 7 % , g l e n o i d

I n i t i a l g l e n o i d d e s i g n

r e v i s i o n

13

r a t e 1 3 %

B o i l e a u

2 1

2 4

3 . 3

8 1 % f o r

7

C T A

1 2 3 d e g r e e f o r C T A

1 2 d e g r e e f o r C T A

9 1 %

C o m p l i c a t i o n r a t e f o r C T A 5 %

I m p o r t a n c e o f t e r e s m i n o r f o r a c t i v e e x

14

t e r n a l r o t a t i o n n o t e d

G u e r y 1 9

6 6

1 4

5 . 8

P a i n s c o r e < 1 0 i n 6 1 %

N R

N R

N R

C o m p l i c a t i o n r a t e 1 1 %

1 0 y s u r v i v a l f r e e o f r e

15

a t 1 0

v i s i o n

y

9 1 % , f r e e o f g l e n o i d f a i l u r e 8 4 %

W a l l 3

1 1 5

1 2 5

3 . 3

M e a n

1 3 7 d e

6 d e g

9 3 %

M o s t c

M u c h

16

0

C o n s t a n t p a i n s c o r e 1 2 . 3

g r e e

r e e

o m m o n c o m p l i c a t i o n s w e r e d i s l o c a t i o n ( 7 . 5 % ) a n d

b e t t e r r e s u l t s i n C T A a n d m a s s i v e c u f f t e a r s

17

i n f e c t i o n ( 4 % )

C u f f

7 0

2 6

2

M e a n

9

A S E S p a i n s c o r e 4 2

1 1 8 d e g r e e

2 8 d e g r e e

9 4 %

D i s l o c a t i o n ( 4 ) , d e e p i n f e c t i

I m p r o v e d r e s u l t s c o m p a r e d t o

18

o n ( 1 ) , a c r o m i a l f r a c t u r e ( 1 ) , g l e n o i d

f i r s t g e n e r a t i o n r e v e r s e p r o s t h e s i s

f a i l u r e ( 1 )

19

CTA, cuff-tear arthropathy; F/U, length of follow-up; ER, external rotation at the side; VAS, visual analogue scale; NR, not reported.

The longest follow-up study to date was reported by Guery et al.19 These authors reported on 80 prostheses implanted mostly in patients with CTA; only 14 shoulders had another etiology. The 10-year survivals free of revision surgery and glenoid loosening were 91% and 84%; however, there was a functional deterioration over time, with less than 61% survivorship of an absolute Constant score over 30 points at 10 years. These authors hypothesized occult aseptic glenoid loosening as a possible explanation for the functional deterioration over time. The results of a reverse design with a lateral center of rotation have been reported by Frankle's group.9 , 14 Frankle et al.14 initially reported on 60 shoulders with rotator cuff deficiency and glenohumeral arthritis followed for an average of 2.7 years after implantation of an Encore reverse prosthesis. The mean P.319

20

visual analogue scale (VAS) pain score improved from 6.3 to 2.2, mean forward flexion improved from 55 to 105 degrees, and the mean ASES score improved from 34 to 68 points. Complications included fractures of the scapula (1 shoulder) or acromion (3 shoulders) and revision for mechanical failure of the glenoid component (8 shoulders).

21

FIGURE 34.3 Preoperative (A) and postoperative (B) radiographs of a patient with CTA treated using a Delta III reverse prosthesis. C: Active elevation after the procedure.

The relatively high failure rate of this glenoid component prompted modifications of the design and surgical technique

22

including the use of 5.0-mm peripheral locking screws and implantation of the baseplate with an inferior tilt. Cuff et al.9 recently reported the results using this second-generation Encore prosthesis in 96 shoulders with massive rotator cuff deficiency (70 shoulders), a failed arthroplasty (23 shoulders), or a proximal humerus nonunion (3 shoulders). At 2 years, the average ASES pain score improved from 15 to 41 points, average flexion improved from 63 to 118 degrees, and average external rotation improved from 13 to 28 degrees. Complications included dislocation (4 shoulders), deep infection (1 shoulder), acromial fracture (1 shoulder), and glenoid failure (1 shoulder). There were no other cases of glenoid mechanical failure or scapular notching (Fig. 34.4). P.320

23

FIGURE 34.4 Preoperative (A) and postoperative (B) radiographs of a patient with

24

CTA treated using an Encore reverse prosthesis. C: Active elevation after the procedure.

SHOULDER HEMIARTHROPLASTY IN CTA Indications Shoulder hemiarthroplasty is considered for patients with CTA and insufficient bone stock to allow the safe implantation of a reverse glenoid component. As mentioned above, some surgeons also consider hemiarthroplasty for patients with relatively well-preserved active motion as well as in the younger patient where the risk of mechanical failure of a reverse prosthesis may outweigh its benefits. Patients should know that the long-term risk of mechanical failure is minimal for hemiarthroplasty18 , 25 , 33 and seems to be much higher for reverse shoulder arthroplasty.19 When mechanical failure is of concern, hemiarthroplasty may be selected, realizing its less satisfactory early clinical outcome.

Technical Aspects The main challenge of shoulder hemiarthroplasty in CTA is to achieve a well-balanced and stable reconstruction while improving pain and range of motion. In an effort to prevent anterosuperior escape, the subdeltoid bursa is incised vertically P.321

from the inferior edge of the coracoacromial ligament distally, but any fibrous tissue in the interval region is left intact. Any remaining subscapularis tendon is incised or released. When

25

passive external rotation is greater than 30 degrees, the subscapularis is incised through tendon; otherwise, it is released from the humerus. The antero-inferior shoulder capsule is released from the humerus, and the humeral head is dislocated anteriorly and inferiorly. The humeral head is resected in approximately 30 degrees of retroversion at the level of the previous insertion site of the supraspinatus tendon. The glenoid may not require any specific preparation, but occasionally it is smoothed or reshaped with the use of a burr or reamer. Some authors have recommended the use of small size heads to decrease tension on any repaired cuff tissue; others use large size heads in order to provide more joint stability. We have found that most of the times a medium-size head fits best. Small heads tend to be unstable and very large heads overstuff the joint. At the end of the procedure, every attempt is made to repair any remaining subscapularis and fibrous tissue on the anterior aspect of the shoulder. Postoperatively, the limb is placed in a shoulder immobilizer that is used during the daytime and at night for 1 month. Patients with hemiarthroplasty for CTA benefit from a limitedgoals type of rehabilitation program. Passive range of motion exercises are started the day after surgery, limiting elevation to 120 degrees and external rotation to 20 degrees. Selfassisted wand exercises and isometrics are started at 6 weeks. Elastic strap strengthening is added at 12 weeks after surgery.

Outcome The results of shoulder hemiarthroplasty for CTA at the Mayo Clinic were published in 2001.25 Thirty-three shoulders were

26

followed for an average of 5 years (range, 2-11 years). The average age of the patients at the time of surgery was 69 years (range, 50-87 years), and 11 shoulders had undergone between one and four previous procedures, including an acromioplasty in eight of them. Shoulder hemiarthroplasty was significantly associated with pain relief. However, at the most recent evaluation, nine patients (27%) had moderate pain at rest or pain with activity. Mean active elevation improved from 72 to 91 degrees (P = 0.008), mean internal rotation improved from L3 to L1 (P = 0.02), and mean active external rotation improved from 36 to 41 degrees (not significant). Strength improved significantly only in external rotation. Using Neer limited goals criteria, successful results were achieved in 22 cases (67%). However, most patients were satisfied with the outcome of the surgery and only four shoulders were subjectively considered to be the same or worse than before the operation. Two factors were associated with a less satisfactory outcome: prior subacromial decompression and the extent of proximal migration of the humeral head. At most recent radiographic evaluation, progression of anterior or superior subluxation was appreciated in 9 of the 31 cases that had complete radiographic follow-up (Fig. 34.5). Eight shoulders had progressive superior erosion of the glenoid, 14 had progressive erosion of the acromion, and two developed an acromial fracture. In addition, eight shoulders developed notching of the medial aspect of the proximal humerus at the level of the inferior rim of the glenoid. None of the components were considered to be radiographically loose or were revised. With the numbers available, neither the

27

humeral head size used nor progression of bone loss was found to influence the outcome of surgery.

FIGURE 34.5 Postoperative anteroposterior radiograph after implantation of a hemiarthroplasty for CTA. Note the superior migration of the humerus.

Table 34.2 summarizes our results as well as those reported by other authors. The percentage of patients with no or mild pain at most recent follow-up after hemiarthroplasty has ranged from 47% to 88%, although subjective satisfaction has been generally higher.2 , 12 , 18 , 25 , 32 , 33 In all series, shoulder hemiarthroplasty provided moderate gains in motion and strength. The main complications observed included instability and symptomatic glenoid erosion.

SUMMARY 28

CTA is characterized by progressive degeneration of the glenohumeral joint in the presence of massive rotator cuff tearing. Calcium-phosphate crystals are commonly found in the synovial fluid, but their role in the pathogenesis of this condition is not completely understood. Patients present with pain and various degrees of motion loss, including pseudoparesis in severe cases. Although arthroscopic debridement and arthrodesis may play a role in some patients, most surgical candidates are best served by reverse total shoulder arthroplasty or humeral head replacement. Reverse shoulder arthroplasty has emerged as the most popular treatment alternative for CTA. The early results of this procedure are impressive, with high rates of pain relief and marked gains in active elevation. However, high complication rates have been reported, and patients with longer follow-up may experience a decline in function and an increase in pain. Multiple modes of mechanical failure have been reported, mostly on the glenoid side, and progressive scapular notching remains a concern with some designs. Shoulder hemiarthroplasty is associated with lower rates of pain relief and modest improvements in range of motion. Persistent pain, anterosuperior instability, and progressive bone loss may complicate the procedure. However, the mechanical failure rate of this procedure is close to zero. Although shoulder hemiarthroplasty is not a perfect answer for patients with CTA, it should be considered for patients with severe glenoid bone loss, as well as younger patients with reasonable preoperative active elevation. P.322

29

TABLE 34.2 REPORTED RESULTS OF SHOULDER HEMIARTHROPLASTY FOR CTA

Stu dy

n

Arn tz2

1 8

F oll o wu p ye ar m ea n (r an ge )

3 (2 10 )b

No or mil d post ope rati ve pain

Active elevatio n preoper ative/po stoperat ive degrees mean (range)

11 (61 %)

66 (4490)/112 (70-160)

Su cce ssf ul res ult sa

NR

Co mm ents

Two reop erati ons for sym pto mati c glen oid eros ion, one for sym pto mati c insta bilit y, and one for

30

post oper ativ e trau mati c fract ure of the acro mio n

Wil lia ms3

2 1

4 (2 7)

18 (86 %)

70 (0155)/120 (15-160)

18 (86 %)

No case s of insta bilit y or reop erati on repo rted

1 6

3 (2 5)

13 (81 %)

60 (4080)/100 (80-130)

10 (62 %)

One intra oper ativ e hum eral shaf t fract ure. Four case s of insta

2

Fiel d12

31

bilit y, two of the m requ iring reop erati on for subs capu laris adva nce men t (one case ) and rese ctio n arthr opla sty (one case )

Zuc ker ma n33

1 5

2 (1 5)

7 (47 %)

69 (20140)/86 (45-140)

NR

11 pati ents (87 %) satis fied with the oper

32

atio n. One case of ante rior insta bilit y

San che zSot elo2

3 3

5 (2 11 )

24 (73 %)

72 (30150)/91 (40-165)

22 (67 %)

One intra oper ativ e hum eral shaf t fract ure. Sev en case s of ante rosu peri or insta bilit y

3 4

3. 7 (2 12 )

30 (88 %)

78 (20165)/111 (40-180)

26 (76 %)

One case of ante rosu peri or insta

5

Gol dbe rg18

33

bilit y, one post oper ativ e acro mio plast y

n: number of shoulders with CTA included in the study; NR: not reported.

a

According to Neer's limited goals criteria.10

b

For shoulders not revised.

References 1. Antoniou J, Tsai A, Baker D, et al: Milwaukee shoulder: Correlating possible etiologic variables. Clin Orthop Relat Res (407):79-85, 2003. 2. Arntz CT, Jackins S, Matsen FA: Prosthetic replacement of the shoulder for the treatment of defects in the rotator cuff and the surface of the glenohumeral joint. J Bone Joint Surg Am 75:485-491, 1993. 3. Arntz CT, Jackins S, Matsen FA: Surgical management of complex irreparable rotator cuff deficiency. J Arthroplasty 6:363-370, 1991. 4. Boileau P, Baque F, Valerio L, et al: Isolated arthroscopic biceps tenotomy or tenodesis improves symptoms in patients

34

with massive irreparable rotator cuff tears. J Bone Joint Surg Am 89(4):747-757, 2007. 5. Boileau P, Chuinard C, Roussanne Y, et al: Reverse shoulder arthroplasty combined with a modified latissimus dorsi and teres major tendon transfer for shoulder pseudoparalysis associated with dropping arm. Clin Orthop Relat Res 466(3):584-593, 2008. 6. Boileau P, Chuinard C, Roussanne Y, et al: Modified latissimus dorsi and teres major transfer through a single delto-pectoral approach for external rotation deficit of the shoulder: As an isolated procedure or with a reverse arthroplasty. J Shoulder Elbow Surg 16(6):671-682, 2007. 7. Boileau P, Watkinson D, Hatzidakis AM, Hovorka I: Neer Award 2005: The Grammont reverse shoulder prosthesis: Results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15(5):527-540, 2006. 8. Boudreau S, Boudreau ED, Higgins LD, Wilcox RB III: Rehabilitation following reverse total shoulder arthroplasty. J Orthop Sports Phys Ther 37(12):734-743, 2007. 9. Cuff D, Pupello D, Virani N, et al: Reverse shoulder arthroplasty for the treatment of rotator cuff deficiency. J Bone Joint Surg Am 90(6):1244-1251, 2008. 10. Ecklund KJ, Lee TQ, Tibone J, Gupta R: Rotator cuff tear arthropathy. J Am Acad Orthop Surg 15(6):340-349, 2007. 11. Favre P, Loeb MD, Helmy N, Gerber C: Latissimus dorsi transfer to restore external rotation with reverse shoulder arthroplasty: A biomechanical study. J Shoulder Elbow Surg 17(4):650-658, 2008. 12. Field LD, Dines DM, Zabinski SJ, Warren RF: Hemiarthroplasty of the shoulder for rotator cuff arthropathy. J Shoulder Elbow Surg 6:18-23, 1997.

35

13. Frankle M, Levy JC, Pupello D, et al: The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients surgical technique. J Bone Joint Surg Am 88(Suppl 1, Pt 2):178-190, 2006. 14. Frankle M, Siegal S, Pupello D, et al: The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 87(8):16971705, 2005. 15. Franklin JL, Barrett WP, Jackins SE, Matsen FA III: Glenoid loosening in total shoulder arthroplasty. Association with rotator cuff deficiency. J Arthroplasty 3(1):39-46, 1988. 16. Garancis JC, Cheung HS, Halverson PB, McCarty DJ: “Milwaukee shoulder”-association of microspheroids containing hydroxyapatite crystals, active collagenase, ad neutral protease with rotator cuff defects. III. Morphologic and biochemical studies of an excised synovium showing chondromatosis. Arthritis Rheum 24(3):484-491, 1981. 17. Gerber C, Pennington SD, Lingenfelter EJ, Sukthankar A: Reverse Delta-III total shoulder replacement combined with latissimus dorsi transfer. A preliminary report. J Bone Joint Surg Am 89(5):940-947, 2007. 18. Goldberg SS, Bell JE, Kim HJ, et al: Hemiarthroplasty for the rotator cuff-deficient shoulder. J Bone Joint Surg Am 90(3):554-559, 2008. 19. Guery J, Favard L, Sirveaux F, et al: Reverse total shoulder arthroplasty. Survivorship analysis of eighty replacements followed for five to ten years. J Bone Joint Surg Am 88(8):1742-1747, 2006.

36

20. Halverson PB, Cheung HS, McCarty DJ, et al: “Milwaukee shoulder”-association of microspheroids containing hydroxyapatite crystals, active collagenase, and neutral protease with rotator cuff defects. II. Synovial fluid studies. Arthritis Rheum 24(3):474-483, 1981. 21. Liem D, Lengers N, Dedy N, et al: Arthroscopic debridement of massive irreparable rotator cuff tears. Arthroscopy 24(7):743-748, 2008. P.323

22. McCarty DJ, Halverson PB, Carrera GF, et al: “Milwaukee shoulder”-association of microspheroids containing hydroxyapatite crystals, active collagenase, and neutral protease with rotator cuff defects. I. Clinical aspects. Arthritis Rheum 24(3):464-473, 1981. 23. Neer CS, Craig EV, Fukuda H: Cuff-tear arthropathy. J Bone Joint Surg Am 65:1232-1244, 1983. 24. Peach CA, Zhang Y, Dunford JE, et al: Cuff tear arthropathy: Evidence of functional variation in pyrophosphate metabolism genes. Clin Orthop Relat Res 462:67-72, 2007. 25. Sanchez-Sotelo J, Cofield RH, Rowland CM: Shoulder hemiarthroplasty for glenohumeral arthritis associated with severe rotator cuff deficiency. J Bone Joint Surg Am 83A(12):1814-1822, 2001. 26. Simovitch RW, Helmy N, Zumstein MA, Gerber C: Impact of fatty infiltration of the teres minor muscle on the outcome of reverse total shoulder arthroplasty. J Bone Joint Surg Am 89(5):934-939, 2007. 27. Sirveaux F, Favard L, Oudet D, et al: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral

37

osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br 86(3):388-395, 2004. 28. Vanhove B, Beugnies A: Grammont's reverse shoulder prosthesis for rotator cuff arthropathy. A retrospective study of 32 cases. Acta Orthop Belg 70(3):219-225, 2004. 29. Visotsky JL, Basamania C, Seebauer L, et al: Cuff tear arthropathy: pathogenesis, classification, and algorithm for treatment. J Bone Joint Surg Am 86-A(Suppl 2):35-40, 2004. 30. Wall B, Nove-Josserand L, O'Connor DP, et al: Reverse total shoulder arthroplasty: A review of results according to etiology. J Bone Joint Surg Am 89(7):1476-1485, 2007. 31. Werner CM, Steinmann PA, Gilbart M, Gerber C: Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total shoulder prosthesis. J Bone Joint Surg Am 87(7):14761486, 2005. 32. Williams GR, Rockwood CA: Hemiarthroplasty in rotator cuff-deficient shoulders. J Shoulder Elbow Surg 5:362-367, 1996. 33. Zuckerman JD, Scott AJ, Gallagher MA: Hemiarthroplasty for cuff tear arthropathy. J Shoulder Elbow Surg 9:169-172, 2000.

38

Chapter 35 Rehabilitation and Activities After Shoulder Arthroplasty Jay Smith Kevin O'Donnell Diane L. Dahm The goal of the rehabilitation is to restore optimal, pain-free function within the anatomic, physiologic, and biomechanical constraints of the patient. Although individualization is a necessity, each rehabilitation program should be based upon fundamental principles reflective of the current scientific knowledge and collective clinical experience.3 , 7 , 8 , 9 , 10 , 70 The purpose of this chapter is to review the principles of rehabilitation following shoulder arthroplasty (Table 35.1). Understanding the principles of shoulder arthroplasty rehabilitation will allow clinicians to develop rationale treatment protocols, while allowing for deviation from protocols when necessary to meet the needs of the individual patient.3 , 7 , 8 , 9 , 10 , 50 , 70

ESTABLISH EFFECTIVE COMMUNICATION Effective communication between the surgeon, patient, patient's family and caregivers, and rehabilitation team members is essential for a successful outcome.8 , 9 , 47 , 70 Realistic goals are established based upon clinical data and diagnostic imaging. Modified or limited goals may be warranted in patients with excessive bone loss, rheumatoid arthritis, failed cuff repair, cuff arthropathy, posttraumatic arthritis, neurological dysfunction, or failed primary shoulder

1

arthroplasty.46 , 50 In such cases, pain control becomes the primary surgical indication, with motion and functional restoration secondary. Patients should visit with a physical therapist during the preoperative period.8 , 9 , 70 The surgeon should communicate to the therapist the case-specific challenges and anticipated modifications to the postoperative program.9 The therapist ensures that the patient and caregivers understand their central roles in the recovery process and outlines the general aspects and time course of the rehabilitation program.8 , 9 , 70 Patient fear and anxiety can be reduced by discussing the management of pain and stiffness in the early postoperative period. As time allows, preoperative exercise instruction should focus on functional lower limb strength and balance training, posture exercises, and scapulothoracic motion and isometric strengthening exercise. Early implementation will minimize deconditioning, reduce the risk of a devastating fall in the postoperative period, and facilitate restoration of scapulothoracic control, a key component of function postarthroplasty.20 , 42 , 45 , 66

OBTAIN ADEQUATE PAIN CONTROL Postoperative pain will not only increase patient and family anxiety and suffering but will also reflexively inhibit the shoulder girdle musculature and impede range of motion (ROM), strengthening, and functional gains.11 , 37 , 68 Pain relief is the primary indication for shoulder arthroplasty in most cases and should take precedence over functional gains.8 , 9 , 50 TABLE 35.1 PRINCIPLES OF REHABILITATION FOLLOWING TOTAL SHOULDER ARTHROPLASTY 2

(1) Establish effective communication

(a)

Surgeon—patient—family—rehabilitation team

(b)

Preoperative as well as postoperative

(2) Obtain adequate pain control

(a)

Preemptive analgesia for exercise sessions

(b)

Medications

(c)

Modalities

(3) Initiate early, atraumatic motion

(a)

Individualized parameters

(b)

Immobilization

(c)

Establishing the ROM program

(d)

The plane of the scapula

(e)

The scapulothoracic articulation

3

(4) Optimize upper limb function

(a)

Realistic goals established preoperatively, modified as necessary

(b)

Appropriate strengthening

(c)

Address kinetic chain to support shoulder

(5) Provide counseling regarding activities

The patient and family should be reassured that postoperative pain and stiffness are normal and will subside over time. The surgeon and rehabilitation team should reinforce the importance of early motion in controlling pain and stiffness as well as minimizing deconditioning.52 The use of continuous interscalene blocks has been shown to improve pain, ROM, and readiness for hospital discharge following arthroplasty.8 , 9 , 25 , 30 , 31 Analgesic medications should be administered 30 minutes prior to therapy to coordinate their optimal effects with the exercise session.69 After resolution of the acute inflammatory phase, hot packs may be applied preexercise to reduce pain and muscle cocontraction.8 , 9 , 69 Postexercise use of ice packs or cooling devices will reduce pain and inflammation incurred by activity.60 , 69 As necessary, these interventions may be supplemented by other pain-relieving modalities such as electrical stimulation (e.g.,

4

transcutaneous electrical nerve stimulation, TENS) and biofeedback, unless otherwise contraindicated.69

INITIATE EARLY ATRAUMATIC MOTION Early mobilization promotes physiologic collagen formation, minimizes the adverse effects of immobility, and provides the P.325 foundation for functional restoration.2 , 55 As previously stated, ROM also facilitates pain control via proprioceptive mechanisms.52 ROM goals are typically 150 degrees elevation (ELE), 50 degrees external rotation (ER), and T9 internal rotation (IR) for osteoarthritis (OA) patients with intact rotator cuffs, and 20 to 40 degrees less in all directions in OA patients with cuff tears or rheumatoid (RA) patients, who often have some degree of rotator cuff insufficiency.22 , 28 Most daily activities can be performed with approximately 20 to 45 degrees of ELE, ER, and IR.28 Advances in surgical techniques, including deltoid preservation, improved component design and placement, and the restoration of myofascial sleeve tension, have facilitated early ROM in shoulder arthroplasty patients.3 , 7 , 8 , 9 , 70 Despite these advances, there is no single ROM program that can be used for all patients. Each patient's program must be modified based upon case-specific factors. Whereas previous articles and chapters have outlined an array of specific exercises to facilitate motion in the postoperative period, this section will focus on important concepts in designing and modifying ROM exercise progressions for patients following shoulder arthroplasty.3 , 7 , 8 , 9 , 10 , 70

5

Immobilization Many surgeons will immobilize shoulder arthroplasty patients postoperatively. In the absence of guiding scientific evidence, the type and duration of immobilization are based primarily upon surgeon preference, collective clinical experience, and the complexities of the specific case. Immobilization has ranged from a simple sling worn for a week in uncomplicated arthroplasty to 6 weeks in 30 to 40 degrees of abduction and 30 to 40 degrees of ER for reverse total shoulder arthroplasty supplemented by latissimus dorsi and teres major tendon transfer.1 , 3 , 4 , 7 In general, the type and duration of immobilization are influenced by the component design and placement, intraoperative stable ROM, the extent and quality of soft tissue repair, and the presence or absence of concomitant tendon transfers. During this early period of immobilization, the patient may perform ROM exercises for the wrist-hand and elbow, as well as lower limb strengthening, balance, and posture exercises. Deep breathing and scapular retraction exercises are well tolerated and promote thoracic extension and scapulothoracic control.36 , 38 , 39 , 42

ESTABLISHING THE ROM PROGRAM As the period of immobilization-protection ends, several principles become relevant to safely establish an effective ROM program. In general, patients tolerate multiple, short duration sessions per day better than one or two prolonged sessions.8 , 9 , 50 , 70 In practice, three to five 5- to 10-minute sessions per day should be implemented. This high-frequency, short-duration exercise regimen confers several advantages: (a) improved

6

compliance, (b) minimal risk of overuse during any specific session, (c) improved carryover, (d) reduced stiffness from excessive “down time” between sessions.8 , 9 , 21 , 51 , 67 The frequent sessions can be supervised by nurses and family members, with the frequency modulated based upon patient response. The allowable arcs of motion should be defined by the surgeon; specifically discussed with the physical therapist; and conveyed to the patient, nursing staff, and caregivers. Exceeding motion limitations with subsequent tissue injury and potential instability are probably the most feared complication in the early postoperative period.53 , 56 , 59 , 72 With appropriate knowledge, the rehabilitation team can anticipate problems and modify the rehabilitation program accordingly. For example, glenoid retroversion or posterior tissue insufficiency may lead to posterior instability during sagittal plane ELE or horizontal adduction, whereas component anteversion, subscapularis or capsular insufficiency, or rotator cuff deficiency may lead to anterior instability during ELE and ER.15 , 50 , 54 , 56 , 59 , 72 Passive range of motion (PROM) is initially utilized to prevent stiffness, enhance circulation, and inhibit pain via proprioceptive feedback.10 , 52 Typical exercises include pendulum exercises as well as ELE and ER performed by the physical therapist with the patient in a supine position.19 , 48 Scapulothoracic exercises are described below. Intraoperative ROM assessment is essential in high-risk patients to initially determine safe and stable arcs of motion. Progression from PROM to active-assisted range of motion (AAROM) depends primarily on the need to protect a concomitant rotator cuff repair or tendon transfer. AAROM

7

includes some assistance provided by an external force, such as a wand, cane, or pulley device. The transition to AAROM is precarious due to a paucity of science to assist the therapist in controlling the amount of muscle contraction and subsequent shoulder stress. Commonly utilized AAROM exercises are well outlined elsewhere and include supineassisted ELE, ER, and IR; supine-assisted ELE-abduction, standing-assisted IR, pulley-assisted ELE, and integrated kinetic chain exercises (e.g., table walk aways, table slides, wall slides).7 , 8 , 9 , 10 , 19 , 37 , 40 , 48 , 50 , 65 , 70 Proper execution is crucial to optimize benefits and minimize adverse effects. Restoration of ELE is paramount to success and is the primary goal of specific surgeries such as reverse total shoulder arthroplasty.4 , 7 , 46 Patients typically progress from supine-assisted ELE to upright pulley-assisted exercises, as supine exercises impart less stress on the rotator cuff and shoulder.19 , 48 The pulley should be placed at least 12 in. above the patient's head and behind the patient.8 , 9 , 10 Table walk-aways facilitate ELE in the context of the kinetic chain and can be progressed to table slides and wall slides as a prelude to the strengthening phase (Fig. 35.1).37 , 42 , 65 ER is the second most important motion to restore, with 30 to 45 degrees of ER required to avoid significant functional limitations.70 Nonetheless, ER goals are often limited in revision or complex primary total shoulder arthroplasty due to component or soft tissue restrictions (e.g., reverse total shoulder arthroplasty).4 , 7 , 46 In cases in which partial restoration of ER is P.326

feasible, early motion is typically limited to 20 degrees or less

8

in order to prevent stiffness while allowing subscapularis healing. When performing ER exercises, patients should initially maintain the arm at the side with the elbow flexed to 90 degrees in order to promote pure ER. Common exercises include supine cane or wand-assisted ER; supine therapistassisted ER; standing doorway ER; and standing cane, wand, or therapist-assisted ER (Fig. 35.2).8 , 9 , 10 , 50 , 70 Active scapular retraction should be incorporated into ER motions to facilitate scapulothoracic rehabilitation and improve functional upper limb ER.37 , 38 , 42

FIGURE 35.1 Table Walk-Aways—subject rests arm on level surface and steps backward, facilitating ELE.

IR exercises are generally limited to PROM to the level of the chest for the first 4 to 6 weeks to protect the healing subscapularis. PROM may be performed standing or supine

9

and is progressed to AAROM and AROM as tolerated after 4 to 6 weeks.

THE PLANE OF THE SCAPULA The surgeon and team members should recognize the importance of the plane of the scapula (30-45 degrees horizontally adducted from the coronal plane) during all phases of rehabilitation.32 , 40 , 42 All motions should be initiated in the plane of the scapula because this plane of ELE (a) provides maximal congruency for the glenohumeral joint, (b) provides the largest impingement free ROM for the shoulder, (c) promotes normal scapulothoracic mechanics, (d) represents the plane of function for most activities of daily living, (e) places minimal tension on the shoulder's soft tissue envelope following appropriate surgical rebalancing, and (f) transfers strength gains effectively to the sagittal and coronal planes.6 , 8 , 9 , 27 , 34 , 35 , 44 , 46 , 57 , 58 In practice, ELE and ER motions are initiated in the plane of the scapula during all phases of rehabilitation. As the patient's strength and neuromuscular control (NMC) improve, the arc of acceptable horizontal adduction-abduction relative to the scapular plane can be expanded based on need. Although inconclusive, preliminary evidence suggests that patients with reverse total shoulder arthroplasties may progress out of the scapular plane faster than patients with total shoulder or hemiarthroplasties.4 , 7 , 46 It should be recognized that the “plane of the scapula,” that is the plane of maximal glenohumeral congruency, may be altered surgically. In such cases, the surgeon would determine the plane of maximal congruency intraoperatively and communicate this to the rehabilitation team.

10

FIGURE 35.2 Supine wand/cane-assisted ER with towel under elbow to achieve plane of the scapula.

THE SCAPULOTHORACIC ARTICULATION The importance of the scapulothoracic articulation in total shoulder arthroplasty rehabilitation has received little direct attention. The role of the scapula in both shoulder function and dysfunction has been clarified and emphasized in recent years.36 , 37 , 38 , 40 , 41 , 42 , 61 , 62 Scapulothoracic motion significantly contributes to total upper limb motion and is a determinant of overall function.32 , 40 Consequently, abnormal scapular positioning (e.g., protraction) reduces upper limb motion, increases soft tissue strain, and contributes to instability and pain.6 , 36 , 42 Kinematic studies have clearly demonstrated that compensatory increases in scapulothoracic 11

motion contribute to upper limb ELE in shoulder arthroplasty patients.5 , 24 , 66 Consequently, scapulothoracic exercises should be incorporated into the rehabilitation program. Reassuringly, with the exception of concomitant tendon transfers or nerve injury, most shoulder arthroplasty patients have normal or near normal scapulothoracic anatomy and intact scapular stabilizer muscles (e.g., rhomboids, trapezii, serratus anterior). Functional scapulothoracic exercise progressions have been detailed elsewhere.12 , 40 , 42 , 65 During immobilization, the therapist or caregiver can perform PROM, focusing on scapular retraction and upward rotation.12 , 40 Active range of motion (AROM) and manually resisted isometric contractions (scapular ELE, retraction, protraction, and depression) are also performed during this period.40 , 61 Pressing the hand of the immobilized upper limb against the abdomen will activate and potentially injure the subscapularis muscle and is therefore avoided.61 During immobilization, the patient may also perform intentional motions with the nonimmobilized upper limb, including straight forward, cross-body, and downward reaches (Fig. 35.3). Although not studied specifically in arthroplasty patients, the stabilization demands imparted by these motions have been demonstrated to elicit scapular stabilizer muscle activity in the immobilized shoulder girdle, while concomitantly producing minimal rotator cuff activation.42 , 61 , 63 Immediately postimmobilization, inferior glide, and low row exercises can be implemented to strengthen the lower trapezius and serratus muscles while maintaining a position of stability (Figs. 35.4 and 35.5).42

12

FIGURE 35.3 Cross-body reach with unaffected arm during immobilization.

P.327

13

FIGURE 35.4 Inferior Glide Exercise—subject pushes downward on tabletop.

As clinical progress allows, the scapulothoracic rehabilitation program can be advanced to include active assisted and resisted isotonic contractions, active scapulothoracic ROM, scapular clocks, wall slides, table slides, robbery exercises, and lawnmower exercises (Fig. 35.6).12 , 40 , 42 , 65 Particularly for patients with rotator cuff deficiency, scapulothoracic rehabilitation represents an essential and potentially outcome limiting aspect of the rehabilitation process.

14

FIGURE 35.5 Low Row Exercise—subject pushes backward against table while retracting the scapula.

15

FIGURE 35.6 Lawnmower Exercise—Starting and End Positions. Subject completes combined motions of right shoulder extension and ER, as well as scapular retraction. Note: Integration of shoulder girdle exercise into an integrated kinetic chain motion.

OPTIMIZE UPPER LIMB FUNCTION As ROM improves, the rehabilitation program begins to emphasize reestablishment of NMC about the shoulder girdle to achieve the surgeon's and patient's functional goals without sacrificing stability or comfort. This requires not only “strength” but also coordinated muscle activity about the shoulder—referred to as “neuromuscular control” (NMC). To develop strength and NMC, muscle groups are challenged by an external force—gravity, a therapist's hand, or some resistive device such as a free weight or elastic tubing.29 AROM in a gravitational field is the most fundamental method to reestablish NMC, provided that the high quality repetitions are completed within motion arc restrictions. In fact, for many

16

revision and complex primary shoulder arthroplasty patients, active ELE against gravity is the primary end point for the rehabilitation program. Whether this endpoint is sufficient or desirable, compared to more advanced strengthening, is decided and agreed upon by the surgeon, patient, caregivers, and rehabilitation team. Specific exercises and functional progressions for “strengthening” postarthroplasty are detailed elsewhere.7 , 8 , 9 , 10 , 50 , 70 However, surgeons managing arthroplasty patients should be aware of several important concepts to consider when designing and supervising “strengthening” programs for arthroplasty patients. First, as previously discussed, virtually all postarthroplasty patients would benefit from scapulothoracic exercises. Second, unless a concomitant rotator cuff repair has been performed, isometric contractions are generally safe to use early in the rehabilitation period and may be directed at both the scapulothoracic and glenohumeral articulations.7 , 8 , 9 , 70 Isometric contractions maintain and increase strength, should be performed at multiple angles throughout an arc of motion, and can be elicited from many different directions in succession to promote joint stability—a technique known as rhythmic stabilization.13 , 17 , 26 , 43 , 71 Third, all “strengthening” exercises should be initially performed in the scapular plane for reasons previously discussed. Fourth, patients should be educated regarding the adverse effects of fatigue on shoulder function and be instructed to self-monitor for fatigue.14 , 21 , 51 , 64 , 67 Fifth, restoration of optimal scapulothoracic and glenohumeral mechanics may reduce shear across the glenohumeral joint and thereby promote prosthesis longevity.14 , 16 , 23 , 37

17

P.328

As isometric exercises progress and ROM improves, active assisted and resisted motions are implemented. The transition to an independent resisted exercise program may take 6 to 12 weeks in rotator cuff intact patients, and up to 3 to 6 months in combined rotator cuff repair-arthroplasty patients. As previously stated, AAROM in a gravitational field is the most fundamental resisted exercise. The rehabilitation team must determine which motions to train, what level of resistance is necessary, and how to progress the patient efficiently and safely toward their functional goals. As necessary, resisted movements in a reduced gravitational field can be achieved by the following: (a) using the assistance of a therapist, pulley, cane, or wand, (b) positioning the body and the shoulder differently with respect to gravitational pull (e.g., active shoulder ELE in a supine vs. upright position), or (c) changing the normal moment arm of the upper limb (e.g., ELE with the elbow bent vs. straight).8 , 9 , 70 Ultimately, the minimum goal is to achieve the end-point ranges of motion in ELE and ER (if possible) in an upright position against gravity. Thereafter, where appropriate, patients may be instructed in a variety of ELE and ER exercises against additional external loads imparted by free weights or elastic tubing, integrating these shoulder motions into kinetic chain activities (e.g., lawnmower exercises) when possible.9 , 29 , 42 , 70 Patients using elastic resistance should be instructed on appropriate positioning and monitored for increased pain during the strengthening phase; the nonphysiological resistance provided by these

18

bands can commonly result in overstressing or understressing the target musculature.29

PROVIDE COUNSELING REGARDING ACTIVITIES A common concern for the arthroplasty patient is the ability to return to recreational and sporting activities. As techniques and results of shoulder arthroplasty continue to improve, it is likely that arthroplasty will be performed in an increasing number of physiologically younger, active patients. A recent study of sports participation following shoulder arthroplasty by McCarty et al.49 found that 64% of patients surveyed stated they underwent shoulder replacement in order to continue playing sports. A high rate of return was noted for sports such as swimming (86% return), golf (77%), and tennis (75%). The authors noted a lower rate of return for sports such as weightlifting (43% return), bowling (40%), and softball (20%).49 Few guidelines exist with respect to a return to sports. A survey of 100 experienced shoulder surgeons generated a list of recommended sports following shoulder arthroplasty.18 Highly recommended sports included bicycling, croquet, golf, hiking, horseshoes, knitting, running, shuffleboard, swimming, and walking. Sports that were specifically not recommended included baseball, boxing, football, and motor cross. Recommendations were based solely on individual surgeon preference and experience. Golf is one sport, which has been specifically studied in the shoulder arthroplasty patient. Twenty-three of 24 patients were able to resume playing golf following surgery at an average follow-up of 53.4 months.33 The average length of

19

time from shoulder arthroplasty to return to playing golf was 4.5 months, and most patients were reported to achieve their preoperative handicap. In this series of 20 total shoulder arthroplasties and six hemiarthroplasties, playing golf was not found to result in an increased radiographic evidence of component loosening. Specifically, the incidence of radiolucent lines in patients who resumed playing golf was not increased significantly when compared to control group.33 A survey of the members of The American Shoulder and Elbow Society revealed that 91% of shoulder surgeons would encourage patients with shoulder arthroplasty to resume playing golf.33 Most reported placing no limits on the number of golf rounds played weekly; however, nearly one third of the surgeons surveyed recommended hemiarthroplasty for active golfers due to concerns regarding potential glenoid component-related complications. In keeping with the basic rehabilitation principles discussed earlier in this chapter, some general recommendations for return to sport following total shoulder arthroplasty apply. Patients should be counseled that the particular activity or sport in which they are participating should be performed with little or no pain. Functional motion should be regained prior to resuming the activity. Activities placing the patient at risk to fall or jar the shoulder (including contact sports) should be avoided. Sports or activities requiring the shoulder to be placed frequently at extremes of motion should also be avoided. Finally, patients should start a given activity gradually and learn the proper form and technique prior to participation. In summary, when counseling a patient regarding return to sports or other activity following shoulder arthroplasty, it is

20

important to understand the specific ROM and strength requirements for that particular activity as well as the patient's desired level and frequency of participation. Recommendations can then be made on an individual basis.

References 1. Amirfeyz R, Sarangi P: Shoulder hemiarthroplasty for fracture with a conservative rehabilitation regime. Arch Orthop Trauma Surg 128(9):985-988, 2008. 2. Aren A, Madden J: Effects of stress on healing wounds. J Surg Res 20:93-97, 1976. 3. Boardman ND III, Cofield RH, Bengtson KA, et al: Rehabilitation after total shoulder arthroplasty. J Arthroplasty 16(4):483-486, 2001. 4. Boileau P, Trojani C, Chuinard C: Latissimus dorsi and teres major transfer with reverse total shoulder arthroplasty for a combined loss of elevation and external rotation. Tech Shoulder Elbow Surg (8):13-22, 2007. 5. Boileau P, Walch G, Liotard JP: Radio-cinematographic study of active elevation of the prosthetic shoulder. Rev Chir Orthop Reparatrice Appar Mot 78(6):355-364, 1992. 6. Borsa PA, Timmons MK, Sauers EL: Scapular-Positioning Patterns During Humeral Elevation in Unimpaired Shoulders. J Athl Train 38(1):12-17, 2003. 7. Boudreau S, Boudreau ED, Higgins LD, Wilcox RB III: Rehabilitation following reverse total shoulder arthroplasty. J Orthop Sports Phys Ther 37(12):734-743.2007. 8. Brems JJ: Rehabilitation after total shoulder arthroplasty: Current concepts. Semin Arthroplasty (18):55-65, 2007. 9. Brems JJ: Rehabilitation following total shoulder arthroplasty. Clin Orthop Relat Res (307):70-85, 1994.

21

10. Brown DD, Friedman RJ: Postoperative rehabilitation following total shoulder arthroplasty. Orthop Clin North Am 29(3):535-547, 1998. 11. Brox JI, Roe C, Saugen E, Vollestad NK: Isometric abduction muscle activation in patients with rotator tendinosis of the shoulder. Arch Phys Med Rehabil 78(11):1260-1267, 1997. 12. Burkhart SS, Morgan CD, Kibler WB: The disabled throwing shoulder: Spectrum of pathology Part III: The SICK scapula, scapular dyskinesis, the kinetic chain, and rehabilitation. Arthroscopy 19(6):641-661, 2003. 13. Carolan B, Cafarelli E: Adaptations in coactivation after isometric resistance training. J Appl Physiol 73(3):911-917, 1992. 14. Chen SK, Simonian PT, Wickiewicz TL, et al: Radiographic evaluation of glenohumeral kinematics: A muscle fatigue model. J Shoulder Elbow Surg 8(1):49-52, 1999. 15. Cofield RH: Degenerative and Arthritic Problems for the Glenohumeral Joint. Philadelphia, W. B. Saunders, 1990. P.329

16. Collins D, Tencer A, Sidles J, Matsen F III: Edge displacement and deformation of glenoid components in response to eccentric loading. The effect of preparation of the glenoid bone. J Bone Joint Surg Am 74(4): 501-507, 1992. 17. Davies G: A Compendium of Isokinetics in Clinical Usage, 2nd ed. LaCrosse, S&S Publishers, 1985. 18. Dines DM: Activity after shoulder replacement. Orthopedics (Special Edition) 36-69, 1996.

22

19. Dockery ML, Wright TW, LaStayo PC: Electromyography of the shoulder: An analysis of passive modes of exercise. Orthopedics 21(11):1181-1184, 1998. 20. Ebaugh DD, McClure PW, Karduna AR: Three-dimensional scapulothoracic motion during active and passive arm elevation. Clin Biomech (Bristol, Avon) 20(7):700-709, 2005. 21. Ellenbecker TS, Roetert EP: Testing isokinetic muscular fatigue of shoulder internal and external rotation in elite junior tennis players. J Orthop Sports Phys Ther 29(5):275-281, 1999. 22. Fenlin JM Jr, Ramsey ML, Allardyce TJ, Frieman BG: Modular total shoulder replacement. Design rationale, indications, and results. Clin Orthop Relat Res. (307):37-46, 1994. 23. Franklin JL, Barrett WP, Jackins SE, Matsen FA III: Glenoid loosening in total shoulder arthroplasty. Association with rotator cuff deficiency. J Arthroplasty 3(1):39-46, 1988. 24. Friedman RJ: Biomechanics of total shoulder arthroplasty: A preoperative and postoperative analysis. Semin Arthroplasty 6(4):222-232, 1995. 25. Gallay SH, Lobo JJ, Baker J, etal: Development of a regional model of care for ambulatory total shoulder arthroplasty: A pilot study. Clin Orthop Relat Res 466(3):563572, 2008. 26. Garfinkel S, Cafarelli E: Relative changes in maximal force, EMG, and muscle cross-sectional area after isometric training. Med Sci Sports Exerc 24(11):1220-1227, 1992. 27. Greenfield BH, Donatelli R, Wooden MJ, Wilkes J: Isokinetic evaluation of shoulder rotational strength between the plane of scapula and the frontal plane. Am J Sports Med 18(2): 124-128, 1990.

23

28. Hawkins RJ, Bell RH, Jallay B: Total shoulder arthroplasty. Clin Orthop Relat Res (242):188-194, 1989. 29. Hintermeister RA, Lange GW, Schultheis JM, et al: Electromyographic activity and applied load during shoulder rehabilitation exercises using elastic resistance. Am J Sports Med 26(2):210-220, 1998. 30. Ilfeld BM, Vandenborne K, Duncan PW, et al.: Ambulatory continuous interscalene nerve blocks decrease the time to discharge readiness after total shoulder arthroplasty: A randomized, triple-masked, placebo-controlled study. Anesthesiology 105(5):999-1007, 2006. 31. Ilfeld BM, Wright TW, Enneking FK, Morey TE: Joint range of motion after total shoulder arthroplasty with and without a continuous interscalene nerve block: A retrospective, casecontrol study. Reg Anesth Pain Med 30(5):429-433, 2005. 32. Inman VT, Saunders JB, Abbott LC: Observations of the function of the shoulder joint. Clin Orthop Relat Res. (330):312, 1996. 33. Jensen KL, Rockwood CA Jr: Shoulder arthroplasty in recreational golfers. J Shoulder Elbow Surg 7(4):362-367, 1998. 34. Jobe CM: Superior glenoid impingement. Orthop Clin North Am 28(2): 137-143, 1997. 35. Johnston T: Movements of the shoulder joint. A plea for the use of the “plane of the scapula” as the plane of reference for movements occurring at the humeroscapular joint. Br J Surg (25):252-260, 1937. 36. Kebaetse M, McClure PW, Pratt N: Thoracic position effect on shoulder range of motion, strength, and three dimensional scapular kinematics. Arch Phys Med Rehabil (80):945-950, 1999.

24

37. Kibler WB: Shoulder rehabilitation: Principles and practice. Med Sci Sports Exerc 30(4 Suppl):S40-S50, 1998b. 38. Kibler WB: The role of the scapula in athletic shoulder function. Am J Sports Med 26(2):325-337, 1998a. 39. Kibler WB, Livingston B, Bruce R: Current concepts in shoulder rehabilitation. Adv Operative Orthop (3):249-300, 1995. 40. Kibler WB, McMullen J: Scapular dyskinesis and its relation to shoulder pain. J Am Acad Orthop Surg 11(2):142151, 2003. 41. Kibler WB, Sciascia A, Dome D: Evaluation of apparent and absolute supraspinatus strength in patients with shoulder injury using the scapular retraction test. Am J Sports Med 34(10):1643-1647, 2006. 42. Kibler WB, Sciascia AD, Uhl TL, et al: Electromyographic analysis of specific exercises for scapular control in early phases of shoulder rehabilitation. Am J Sports Med 36(9):1789-1798, 2008. 43. Lieberson W: Brief Isometric Exercises in Therapeutic Exercise, 4th ed. Baltimore, Williams and Wilkins, 1984. 44. Lippitt S, Matsen F: Mechanisms of glenohumeral joint stability. Clin Orthop Relat Res (291):20-28, 1993. 45. Mahfouz M, Nicholson G, Komistek R, et al: In vivo determination of the dynamics of normal, rotator cuffdeficient, total, and reverse replacement shoulders. J Bone Joint Surg Am 87(Suppl 2):107-113, 2005. 46. Matsen FA III, Boileau P, Walch G, et al.: The reverse total shoulder arthroplasty. J Bone Joint Surg Am 89(3):660667, 2007.

25

47. Maybach A, Schlegel TF: Shoulder rehabilitation for the arthritic glenohumeral joint: Preoperative and postoperative considerations. Semin Arthroplasty 6(4):297-304, 1995. 48. McCann PD, Wootten ME, Kadaba MP, Bigliani LU: A kinematic and electromyographic study of shoulder rehabilitation exercises. Clin Orthop Relat Res (288):179-188, 1993. 49. McCarty EC, Marx RG, Maerz D, et al.: Sports participation after shoulder replacement surgery. Am J Sports Med 36(8):1577-1581, 2008. 50. McCluskey G, Uhl TL: Total Shoulder Replacement, 3rd ed. New York, Churchill Livingstone, 1997. 51. McQuade KJ, Dawson J, Smidt GL: Scapulothoracic muscle fatigue associated with alterations in scapulohumeral rhythm kinematics during maximum resistive shoulder elevation. J Orthop Sports Phys Ther 28(2):74-80, 1998. 52. Melzack R, Wall PD: Pain mechanisms: A new theory. Science 150(699): 971-979, 1965. 53. Moeckel BH, Altchek DW, Warren RF, et al: Instability of the shoulder after arthroplasty. J Bone Joint Surg Am 75(4):492-497, 1993. 54. Mullaji AB, Beddow FH, Lamb GH: CT measurement of glenoid erosion in arthritis. J Bone Joint Surg Br 76(3):384388, 1994. 55. Muller EA: Influence of training and of inactivity on muscle strength. Arch Phys Med Rehabil 51(8):449-462, 1970. 56. Noble JS, Bell RH: Failure of total shoulder arthroplasty: Why does it occur? Semin Arthroplasty 6(4):280-288, 1995. 57. Saha AK: Mechanics of elevation of glenohumeral joint. Its application in rehabilitation of flail shoulder in upper

26

brachial plexus injuries and poliomyelitis and in replacement of the upper humerus by prosthesis. Acta Orthop Scand 44(6):668-678, 1973. 58. Saha AK: The classic. Mechanism of shoulder movements and a plea for the recognition of “zero position” of glenohumeral joint. Clin Orthop Relat Res (173):3-10, 1983. 59. Sanchez-Sotelo J, Sperling JW, Rowland CM, Cofield RH: Instability after shoulder arthroplasty: Results of surgical treatment. J Bone Joint Surg Am 85-A(4):622-631, 2003. 60. Singh H, Osbahr DC, Holovacs TF, et al: The efficacy of continuous cryotherapy on the postoperative shoulder: A prospective, randomized investigation. J Shoulder Elbow Surg 10(6):522-525, 2001. 61. Smith J, Dietrich CT, Kotajarvi BR, Kaufman KR: The effect of scapular protraction on isometric shoulder rotation strength in normal subjects. J Shoulder Elbow Surg 15(3):339-343, 2006. 62. Smith J, Kotajarvi BR, Padgett DJ, Eischen JJ: Effect of scapular protraction and retraction on isometric shoulder elevation strength. Arch Phys Med Rehabil 83(3):367-370, 2002. 63. Smith J, Padgett DJ, Dahm DL, et al: Electromyographic activity in the immobilized shoulder girdle musculature during contralateral upper limb movements. J Shoulder Elbow Surg 13(6):583-588, 2004. 64. Teyhen DS, Miller JM, Middag TR, Kane EJ: Rotator cuff fatigue and glenohumeral kinematics in participants without shoulder dysfunction. J Athl Train 43(4):352-358, 2008. 65. Uhl TL, Carver TJ, Mattacola CG, et al: Shoulder musculature activation during upper extremity weight-bearing exercise. J Orthop Sports Phys Ther 33(3):109-117, 2003.

27

66. Veeger HE, Magermans DJ, Nagels J, et al: A kinematical analysis of the shoulder after arthroplasty during a hair combing task. Clin Biomech (Bristol, Avon) 21(Suppl 1):S39S44, 2006. 67. Voight ML, Hardin JA, Blackburn TA, et al: The effects of muscle fatigue on and the relationship of arm dominance to shoulder proprioception. J Orthop Sports Phys Ther 23(6):348-352, 1996. 68. Warner JJ, Micheli LJ, Arslanian LE, et al: Patterns of flexibility, laxity, and strength in normal shoulders and shoulders with instability and impingement. Am J Sports Med 18(4):366-375, 1990. 69. Weber D, Brown A: Physical Agent Modalities. Philadelphia, W.B. Saunders, 1996. 70. Wilcox RB, Arslanian LE, Millett P: Rehabilitation following total shoulder arthroplasty. J Orthop Sports Phys Ther 35(12):821-836, 2005. 71. Wilk KE, Meister K, Andrews JR: Current concepts in the rehabilitation of the overhead throwing athlete. Am J Sports Med 30(1):136-151, 2002. 72. Wirth MA, Rockwood CA Jr: Complications of shoulder arthroplasty. Clin Orthop Relat Res. (307):47-69, 1994.

28

Chapter 36 Complications in Shoulder Arthroplasty Steven J. Hattrup In the modern surgical era, Neer introduced prosthetic replacement for proximal humeral fractures in the early 1950s and glenoid resurfacing approximately two decades later.58 , 60 , 61 Over time, the design of shoulder prostheses has evolved in both number and complexity to allow greater adaptation to underlying pathology. Anatomic design prostheses are now available, which allow bone ingrowth or cement fixation, adjustment of head height, version, offset, and diameter, and variable conformity between the glenoid and humeral surfaces. Reverse designs have been approved for the rotator cuff deficient shoulder. Concurrent with the design changes, shoulder arthroplasty has become more common, with the frequency roughly doubling from 1998 to 2005.101 Despite the increasing experience with shoulder replacement, the rate of complications remains at approximately 12% to 15% for anatomic designs.6 , 18 , 96 The incidence of complications with reverse arthroplasty is even higher, with reported rates of up to 34% to 75%.5 , 93 , 94

ANATOMIC SHOULDER ARTHROPLASTY Incidence How complications are defined differs between authors. In 1982, Neer published a series of 37 consecutive shoulder replacements requiring revision surgery.59 The indications for revision surgery perhaps reflected the then less sophisticated state of shoulder surgery. These included the presence of a

1

radical acromionectomy or other anterior deltoid deficiency, overtightened subscapularis, subacromial impingement, loss of humeral length, prominent greater tuberosity, and inadequate rehabilitation. Neer encouraged consideration of four conditions in order to minimize complications, which remains just as valuable today.61 These are the presence of humeral or glenoid bone deficiency, the possibility of a defective rotator cuff, prior deltoid injury, and chronic instability patterns. A series of reports documents the evolving Mayo Clinic experience over time.18 , 19 , 22 The initial series was composed of revision surgeries from 1976 through 1988. The most common problems were glenoid loosening in total shoulder arthroplasty (TSA) and glenoid arthrosis in humeral head replacement (HHR).19 In a subsequent analysis of revision TSA from 1981 through 1991, the most common indications for reoperation were instability and rotator cuff tearing followed by glenoid or humeral loosening.22 Glenoid arthrosis remained the prime indication for revision surgery in HHR. Finally, complications were examined in a consecutive series of 431 TSA performed between 1990 and 2000.18 Rotator cuff tearing and instability remained the most common indications for further surgery. Only a single case of revision surgery for component loosening was found. Another perspective on the incidence and distribution of complications in shoulder replacement is provided by several meta-analyses of published series. Wirth and Rockwood97 examined the complications that occurred in over 1600 shoulder arthroplasties found in 32 peer-reviewed articles. They found that component loosening, instability, rotator cuff tearing, periprosthetic fracturing, infection, implant structural

2

failure, and deltoid weakness or dysfunction were the most common complications in descending order of frequency. However, many of the reports provided only relatively shortterm follow-up. This group returned to this subject in 2006.4 Thirty-three studies with 2540 shoulders at an average follow-up of 5.3 years were scrutinized. Again in descending order of frequency, component loosening, instability, periprosthetic fracturing, rotator cuff tearing, neural injury, infection, and deltoid dysfunction were the most common complications. Van de Sande86 studied 40 publications with 3584 replacements to conclude component loosening was the most common complication followed by instability, periprosthetic fracture, nerve injury, and infection. The definition of failure should also include patient dissatisfaction. Pain (present in 82% of cases) and stiffness (in 74%) were the most common factors associated with dissatisfaction in one recent report.38 Hasan38 also found that almost one quarter of patients chose not to have further surgery on their shoulder, and studies of revision rates alone would, therefore, underestimate complication rates. Complication rates will also be influenced by length of patient follow-up. Certain complications such as loosening will necessarily be underrated by shorter-term follow-up (Fig. 36.1). Conversely, long-term follow-up of shoulder arthroplasty can potentially inflate the prevalence of some complications due to inclusion of cases early in the learning curve. The assessment of complications is a dynamic process as surgical techniques evolve and experience is gained.

Instability

3

Instability is reported after 4% to 5% of TSA, and even more commonly after HHR.4 , 86 Directions can be superior, inferior, posterior, or anterior. Instability can not only be responsible for painful subluxation and dislocation episodes, but also is related to wear, particulate synovitis, osteolysis, and premature loosening of both glenoid and humeral components.1 , 29 , 47 , 67 , 72 , 79 , 82 , 91 The most frequently recognized pattern is superior displacement. Although it is commonly associated with rotator cuff tearing, Boyd has shown that other issues can be responsible as well7 (Fig. 36.2). He evaluated factors associated with postoperative proximal migration of the humeral P.331

component in 131 shoulder replacements. Intraoperatively, 28 of 131 (21%) shoulders were discovered to have a torn rotator cuff. Postoperatively, 7 of these 28 shoulders (25%) with a documented tear were found to have proximal migration compared to 22 of 103 (21%) shoulders an intact cuff. The lack of correlation between progressive humeral migration and rotator cuff tearing led Boyd to conclude that several factors are relevant to postoperative proximal migration. These include an increased glenoid facing angle, release of the coracoacromial ligament, an irreparable rotator cuff tear, proud placement of the humeral component, and dynamic imbalance between a strong deltoid and an attenuated, dysfunctional rotator cuff. Superior instability can also be produced by deltoid injury. Groh et al.36 described 12 cases of deltoid dysfunction after shoulder replacement. Ten lost function of the anterior and middle deltoid due to a failed repair, and two had complete deltoid loss from axillary

4

neuropathy. Average forward flexion was only 33 degrees, and anterosuperior dislocation was common with attempted elevation.

5

FIGURE 36.1 This patient presented with symptomatic osteoarthritis of his shoulder,

6

with typical findings of joint space narrowing, osteophyte formation, and posterior erosion of the glenoid (A,B). TSA was performed with an excellent clinical result (C,D). Nine years later, he presented with 3 months of shoulder pain. Radiographs demonstrated posterior erosion of the polyethylene and metal tray, with subluxation of the joint (E,F). Revision surgery to an all-polyethylene glenoid component with stem exchange was successful.

P.332

FIGURE 36.2 This stem was seated quite proud, producing superior displacement of the joint with subsequent loosening of the glenoid and erosion of the humeral calcar. The rotator cuff was actually intact.

7

Treatment of superior instability in shoulder arthroplasty is dependent on the etiology and symptoms. Fortunately, often the symptoms are relatively mild and little may need to be done.97 , 7 In the symptomatic shoulder, revision surgery is necessary for component malposition. The most challenging issue is the combination of an absent coracoacromial ligament with cuff tearing. This is commonly associated with failed prior attempts at rotator cuff repair. These patients can suffer from profound and painful prominence of the humeral head under the antero-superior shoulder surface as containment within the coracoacromial arch is lost. Reconstruction is difficult, and results are often poor.27 , 30 , 32 , 54 , 95 Wiley reported on four patients with severe superior dislocation after coracoacromial ligament resection; three were associated with cuff repair attempts and two with HHR.95 In two patients containment of the humeral head was reestablished with iliac crest bone graft of the coracoacromial arch in conjunction with capsular release. Both patients had improvement of their pain. Alternatively, soft tissue reconstruction can be attempted with pectoralis major tendon transfer or tendo Achilles' allograft but failures remain common.30 , 54 Revision reverse shoulder arthroplasty is typically the only reliable option for this instability pattern. Although often transiently seen from deltoid atony, persistent inferior instability is primarily an issue of loss of humeral length after acute fracture reconstruction (Fig. 36.3). Loss of length not only produces painful inferior subluxation or dislocation of the joint but also inefficient deltoid function from inadequate muscle tension. The best treatment is avoidance by reconstruction of adequate length in the

8

humeral shaft during prosthetic replacement. If a replacement is inferiorly positioned, it can only be corrected by revision of the stem for proper tensioning of the soft tissues. Anterior instability is generally related to failure of the subscapularis repair with abnormal capsular tensioning56 , 63 , 68 (Fig. 36.4A,B). Moeckel et al.56 found 10 cases of revision surgery for instability out of 236 shoulder replacements. Seven cases were anterior, and all were felt secondary to a ruptured subscapularis. Four of these seven had successful primary repair of the subscapularis, and three required Achilles' tendon allograft to reestablish stability. In a series of 11 patients undergoing repeat surgery for instability, Wirth described three shoulders with anterior dislocation.97 Several problems were noted to be potentially responsible. All three replacements were found to have decreased humeral retroversion, two had a ruptured subscapularis, and one shoulder had anterior glenoid erosion. Factors found contributing to the failure of the subscapularis were usually poor technique, inadequate tissue, inappropriate physical therapy, and oversized components placing excessive tension on the repair. Treatment of anterior instability involves evaluation of the underlying cause, especially the integrity of the subscapularis in addition to component position.68 The position of the glenoid component should be checked to ensure that anterior erosion P.333

from problems, such as rheumatoid arthritis or posttraumatic arthritis, has not led to increased glenoid anteversion. Version of the humeral component is likewise assessed.

9

Retroversion can be increased to 30-40 degrees, but excessive retroversion needs to be avoided so as not to precipitate posterior instability. Excessive tightness in the posterior capsule can be associated with anterior laxity, and release is occasionally necessary to balance the soft tissues. The most important step is restoration or reconstruction of the anterior capsule and subscapularis. If the subscapularis cannot be securely repaired, then reconstruction will be necessary. Potential techniques include calcaneal-tendo Achilles allograft or pectoralis major tendon transfer. Both techniques have been successful, but failures are common.30 , 56 , 97 As for other problems of soft tissue deficiency, reverse revision arthroplasty may be the better solution, especially in the elderly patient.

10

FIGURE 36.3 Although not initially fractured, this humerus was fractured due to excessive impaction force to achieve press-fit fixation. Rather than cementing the stem at the appropriate height, the surgeon chose to repair the tuberosities around the malpositioned stem. The inferior subluxation of the prosthesis led to pain and poor function.

11

FIGURE 36.4 A,B: The subscapularis repair in this patient with rheumatoid arthritis failed, resulting in anterior instability and poor function.

The etiology of posterior instability tends to be multifactorial and can be associated with many of the abnormalities typically found in the osteoarthritic shoulder. These include anterior capsular tightness, erosion of the posterior aspect of the glenoid, secondary increased retroversion of the glenoid, posterior subluxation of the humerus, and redundancy of the posterior capsule (Fig. 36.5).3 , 62 Failure to recognize and correct for these changes during the primary procedure can leave the patient with an unstable reconstruction. Moeckel et al.56 in his series of 10 revisions for instability, reported three shoulders with posterior instability. Contributing problems were found to be excessive retroversion of the glenoid component, capsular redundancy, and humeral malposition. Surgical treatment consisted of a case of glenoid

12

revision with posterior glenoid bone grafting, one instance of humeral revision to diminish the humeral retroversion, and a final procedure of posterior soft tissue repair. The case of posterior capsulorrhaphy was unsuccessful. Wirth and Rockwood97 described the surgical pathology in seven shoulders with posterior instability. Similar issues by Moeckel were reported, including excessive humeral retroversion of over 45 degrees in four patients, posterior glenoid erosion in four shoulders, and a single instance of nonunion of the greater tuberosity. After revision surgery in a total of 11 cases of instability problems, restoration of stability was accomplished in 10 shoulders and pain relief was uniform. P.334

Average postoperative flexion was 100 degrees and external rotation 35 degrees.

13

FIGURE 36.5 A,B: This posteriorly dislocated shoulder exhibits substantial retroversion of the glenoid component and inferior positioning of the humeral component. The surgeon unsuccessfully attempted to compensate with increased anteversion of the humeral component and a large head size.

14

The experience at the Mayo Clinic for correction of prosthetic instability has not been as successful. Sanchez-Sotelo et al.68 reported 33 cases treated surgically. The etiology was felt due to soft tissue deficiency in 21 shoulders, component malposition alone in only 1, and a combination of both problems in the remaining 11. Nineteen cases had an anterior instability pattern and 14 posterior. The initial procedure corrected the instability in only 9 shoulders (28%) and in a total of 14 (44%) after further procedures. Instability of shoulder arthroplasty is very challenging to treat, and the surgeon must be prepared to correct all the deficiencies present. Even then, the instability pattern can recur.

Rotator Cuff Tear Rotator cuff tearing is described in 1% to 2% of patients, although this may be an underestimation.4 , 62 A retrospective review found diminished subscapularis function in approximately two thirds of shoulders.55 Tears are found most commonly anteriorly in the subscapularis or superiorly through the medial extent of the arthrotomy.4 , 39 While frank rupture can occur, frequently the arthrotomy repair stretches out during the rehabilitation. The tendon interval fills with scar tissue, leaving the musculotendinous unit at an ineffective length. Tears are associated with prior surgery, tendon lengthening, use of an oversized humeral head, and aggressive therapy.54 Less often, the posterior aspect of the cuff is injured during the humeral neck osteotomy. A tear can be associated with instability or by failure to progress at the expected rate in physical therapy. The diagnosis is relatively easy to make if dislocation has occurred, and early repair can be planned. It can be more

15

challenging to establish the diagnosis in a stable shoulder, and failure of the cuff must be differentiated from other causes of pain and dysfunction, such as stiffness, neurologic injury, deltoid damage, and incomplete patient cooperation. The shoulder with a failed arthrotomy repair occurring through inappropriate physical therapy or poor tissue can present earliest with excessive passive range of motion, especially in external rotation. As the patient progresses into active motion exercises, poor motion with disrupted glenohumeral rhythm is indicative of cuff failure. The lift-off and belly press signs are useful to judge the subscapularis integrity. Due to the need to protect a potentially intact repair, weakness on manual strength testing is a late finding. On radiographic examination, proximal humeral migration or anterior subluxation can be evident. While proximal humeral migration can be associated with other factors, as the acromiohumeral distance narrows, it becomes increasing less likely there is any cuff present superiorly7 (Fig. 36.6). Arthrographic studies may not be conclusive, but CT arthrography is the most useful test in our hands and can be combined with aspiration for culture. While diagnostic when positive, the tendon gap is often filled with scar tissue, obstructing the flow of the contrast material. While some have found MRI studies useful, they are subject to severe artifact distortion.80 Repair is carried out when instability or dysfunction indicates. Fortunately, many patients have little pain and tolerable function.2 , 23 When surgery is attempted, the procedure can be challenging and failures common.30 , 42 , 43 , 54 , 55 In 19 cases of cuff repair in a prosthetic shoulder, a successful outcome was accomplished in only four cases.55 The average postoperative elevation obtained was only 78 degrees.

16

Pectoralis major transfer for anterosuperior instability associated with rotator cuff deficiency was found to reestablish stability in only 7 of 14 cases, and only 3 shoulders had elevation above the horizontal.30 Due to these poor results, the surgeon should consider reverse shoulder revision arthroplasty in the elderly patient.

FIGURE 36.6 When marked superior subluxation of the humeral component is present, the diagnosis of rotator cuff tearing is obvious. The shoulder was salvaged by conversion to a reverse prosthesis.

Repair is carried out through the original incision for the deltopectoral approach. Skin flaps are developed to allow a deltoid splitting approach to the rotator cuff if there is any superior or posterior cuff involvement. If the problem is

17

subscapularis tearing, the deltopectoral incision offers the best exposure, and in all instances, deltopectoral access must be available in case humeral head or stem revision is found necessary. The margins of the remaining rotator cuff are then carefully identified, realizing that scar tissue and remaining bursal tissue can obscure the true tendon edges. With protection of the axillary nerve, circumferential mobilization of the tendons from both extra-articular scar tissue and adhesions along the glenoid margin is essential. The tendons are repaired back to prepared bone beds on the greater and lesser tuberosities as appropriate through bone tunnels. Assessment of the size of the humeral head should be performed as part of the process. An oversized head will place excessive tension on the repair. If a large head size was chosen to establish stability, then correction of component version or other factors contributing to the instability needs to occur to allow use of an appropriately sized head. As in all cases of shoulder reconstruction, guidance should then be given to the physical therapist for safe motion limits.

Periprosthetic Fracture The incidence of periprosthetic humeral fractures is approximately 1% to 2% of shoulder replacements.4 , 12 , 18 , 61 , 85 , 86 , 89 , 98 These fractures can be difficult to manage. They are often unstable due to increased torsional stresses at the tip of the humeral stem from restriction of motion at the glenohumeral joint and can have poor healing from loss of the endosteal blood supply.10 , 100 P.335

18

Wright and Cofield100 have classified humeral fractures around a stem as Type A, B, or C (Fig. 36.7). Type A fractures are centered at the tip of the prosthesis and extended proximally at least one third the length of the stem. Type B fractures are primarily centered at the tip of the stem and extend distally, and Type C fractures involve the humeral shaft distal to the prosthesis. An alternative but similar classification system was described by Worland and Yung.99 Type A fractures were proximal fractures occurring about the tuberosities. Type B fractures were located about the tip of the prosthesis and were subdivided into three categories. Spiral fractures around a stable prosthesis were B1 fractures, transverse or short oblique fractures with a stable stem were B2, and B3 fractures had an unstable prosthesis. If the fracture was distal to the stem, it was classified as Type C. These fractures occur from surgical error intraoperatively or from a traumatic event postoperatively. During surgery, a number of events can lead to a fracture and should be avoided. Care must be taken with the exposure in a tight shoulder with osteopenic bone. Excessive torque during dislocation without adequate capsular release can easily produce a fracture. A second mechanism of injury to the shaft can occur during reaming of the shaft. In a posttraumatic shoulder, distortion of anatomy can lead to eccentric reaming and breakthrough the cortical canal. Additionally, reaming can damage the canal if done overzealously. The humeral cortex is often thin, especially in rheumatoid shoulders. An aggressive approach to the canal will produce a fracture. Finally, forceful impaction of the stem in an attempt to obtain

19

a tight press-fit in weak bone is unsafe and can fracture the shaft. Groh et al.34 has reported on 12 humeral fractures. Eight occurred intraoperatively and four postoperatively from an injury. Of the primary fracture cases, two resulted from manipulation of the extremity, one from reaming, one during broaching, and the final two subsequent to the insertion of the prosthesis. Two additional fractures developed in areas of cortical thinning during revision surgery. Campbell et al.14 described 21 fractures; 16 were an intraoperative complication and 5 happened postoperatively. The most common contributing factor was osteopenia, found in 75% of the extremities. In the seven fractures Boyd et al.10 discovered after 436 replacements, all occurred late. Six ensued from a fall and one from a motor vehicle accident. Five of the patients had rheumatoid arthritis, a population frequently suffering from osteopenia. Similarly, Wright found cofactors of advanced osteopenia in six shoulders and an ipsilateral elbow replacement in two extremities out of nine late humeral fractures after 499 TSA.100 The particular risk that ipsilateral stemmed shoulder and elbow replacements pose to the rheumatoid extremity was delineated. Any vacant segment between the stems or cement columns results in a stress riser. Gill and colleagues33 recommended use of cemented stems with a continuous cement column to avoid this problem. Risk factors in addition to osteopenia and rheumatoid arthritis include increased age, female sex, and glenoid resurfacing.81

20

FIGURE 36.7 The Wright-Cofield classification of periprosthetic humeral fractures is shown here. See text for detailed description.

Treatment of periprosthetic humeral fractures is complicated by the fact that intraoperative fractures are often not recognized until a postoperative x-ray. It is often tempting to treat the fracture nonsurgically, but the outcome can be poor unless the fracture is stable. Bonutti and Hawkins6 attempted to treat four fractures conservatively, three of which were suffered intraoperatively. All failed to heal. He recommended consideration of “vigorous treatment” of these fractures. Boyd et al.10 treated seven fractures after arthroplasty conservatively. Six fractures failed to heal and only one 21

initially went on to union. One patient refused further treatment; five united after surgical fixation. Boyd concluded open reduction and fixation was the preferable treatment. Kligman and Roffman46 described five fractures associated with HHR; three of the five did heal without surgery. However, time to union was 7 months and only one had a satisfactory result. In comparison, the two treated surgically healed in 2 months. Wright and Cofield100 similarly reported difficulty with nonsurgical treatment in their series of nine fractures. Four did heal without surgery but three others went onto nonunion. Two of these three healed with revision surgery and bone grafting and the two treated primarily with internal fixation also healed. They, therefore, felt that while long oblique and spiral fractures could be managed conservatively, it was better to internally stabilize transverse and short oblique fractures at the tip of the stem or if associated with a loose prosthesis. Distal fractures can be managed conservatively. Groh did successfully manage three such fractures with a fracture brace with union at 9 weeks.34 The value of aggressive treatment of these fractures was detailed by Campbell.14 They found improved healing with anatomic reduction and stable fixation. There was significantly less time to union, less influence on rehabilitation, and a trend toward fewer complications. Similarly, anatomic reduction to within 2 mm of displacement was statistically associated with diminished healing time. There is therefore a fairly uniform agreement on the value of operative treatment for the majority of these injuries.10 , 14 , 33 , 34 , 99 , 100 Fractures discovered intraoperatively should be stabilized with cerclage wires and a long stem component as needed to create a stable

22

construct that allows early range of motion postoperatively (Fig. 36.8A,B). The tip of the prosthesis should extend two to three cortical diameters beyond the level of the fracture. Postoperatively discovered fractures that are proximal to the tip of the stem, especially long oblique or spiral patterns, may be stable enough to treat nonoperatively (Wright Type A, Worland Type A and B1). However, transverse and short oblique fractures require internal stabilization with cerclage cables and a long stem prosthesis if the fracture extends to within two to three cortical diameters of the stem tip (Wright P.336

Type B, Worland Type B2 patterns). Similarly, injuries involving an unstable implant are best revised to a long stem construct (Worland Type B3). The more distal fractures classified as Type C by both Wright and Worland can be treated on their merits with either internal fixation or bracing as the fracture pattern and potential elbow involvement dictate. Inclusion of an iliac crest bone graft does not seem to be necessary.35

23

FIGURE 36.8 A: This shaft was fractured intraoperatively. The surgeon chose to try to treat the fracture nonoperatively rather than stabilizing the injury. The fracture not only failed to heal, but the prosthesis was not secure and subsided to an unacceptable position. B: Treatment of this required stem revision to a more appropriate level and use of a long stem component with cerclage cables for fracture fixation. The fracture healed within 2 months.

Glenoid fractures are less common or at least less troublesome. There are isolated reports but no large series of these injuries.42 , 82 , 85 The glenoid rim is vulnerable from the torque applied by reaming, especially when done under power in weak bone. As long as the vault of the glenoid is left intact, resurfacing can still be carried out. Downsizing the choice of the glenoid may be necessary to ensure adequate bone support of the component. If fracture into the glenoid neck occurs, stable fixation with either peg or keeled designs cannot be achieved. The only option in this case is to pack

24

the glenoid defect with bone graft from the humeral head and convert to HHR with contouring of the remaining glenoid surface to conform to the humeral head.

Infection Infection is an uncommon problem, but it can pose a challenge to diagnose and therefore should be considered whenever there is unexplained pain or premature loosening in a replacement2 , 4 , 48 , 61 , 85 , 86 , 89 (Fig. 36.9A-D). Bohsali et al.4 and Van de Sande et al.86 calculated an overall incidence of 0.7% to 0.8%. Consequently, most surgeons develop limited experience with infected shoulder prostheses, yet a high index of suspicion must be maintained due to the consequences of failure of treatment if infection is not recognized. Risk factors associated with a higher incidence of infection are systemic immune disorders and multiple prior surgeries.48 Pain is the most consistent symptom of an infected shoulder replacement.48 Other signs and symptoms such as overt drainage, an effusion, erythema, stiffness, and fever may or may not be present. Consequently, all failed arthroplasties are considered infected until proven otherwise. Laboratory studies of potential value include a white blood cell count with differential, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) and are routinely ordered. Additional studies may be indicated. If there is a higher index of suspicion for infection such as from premature failure of the arthroplasty, or the screening tests are abnormal, then aspiration for cell count and culture should be obtained. An Indium-111 scan can be useful as well in difficult cases but is not routinely obtained. Ultimately, the diagnosis may rely on

25

intraoperative histology and cultures for final diagnosis. Nevertheless, despite very careful preoperative evaluation, potential infection can still be missed.84 The most common infecting organisms have historically been reported to be Staphylococcus aureus and coagulasenegative Staphylococcus.4 , 48 More recently, the importance of Propionibacterium acnes, as an infecting organism, has been increasingly recognized.4 , 83 , 84 However, Propionibacterium can be difficult to isolate and may require prolonged incubation of cultures. Cultures from joints with prior surgery are kept for 10 days at our institution. While a number of treatment options are reported for these patients, treatment usually mimics the treatment of infected hip and knee arthroplasty with a two-stage exchange arthroplasty.24 , 48 , 83 Kozak et al.48 found that this was uniformly successful in three shoulders, all of which were free of infection at most recent follow-up with superior function compared to the other treatment groups. This same group subsequently reported a larger series with less promising results.83 Out of 19 shoulders, the infection was cured in 12 (63%), but clinical outcomes were excellent in only 2, satisfactory in 4, and unsatisfactory in 13 shoulders. P.337

26

FIGURE 36.9 This 80-year-old man presented with persistent mechanical pain despite HHR 2 years earlier. He had subsequently undergone diagnostic arthroscopy and acromioplasty without improvement of symptoms. No substantial inflammation was appreciated at the time of the arthroscopy. Presenting radiographs revealed an undersized but solid humeral component. The glenoid showed severe wear and

27

erosion (A). At surgical exploration, histologic analysis showed significant acute inflammation. Resection arthroplasty was performed with insertion of a temporary spacer (B). Intravenous antibiotics were administered for 6 weeks, when second-stage reconstruction was subsequently carried out (C,D).

Other treatments options included debridement with prosthesis retention, one stage exchange arthroplasty, and resection arthroplasty. Of seven shoulders where the prosthesis was preserved in conjunction with debridement in Kozak's series, it was subsequently removed in four.48 These authors concluded that eradication of infection necessitated component removal as either the definitive treatment or as part of two-stage exchange arthroplasty. They did attempt a single stage exchange arthroplasty in two shoulders with recurrent deep infection in one. Better results with single exchange were described in the two series of Ince and Cuff.25 , 44 There were no recurrences of infection in a total of 19 shoulders. Resection arthroplasty P.338

leaves the patient with poor function, and surprisingly often with persistent infection as well.11 , 48 The current treatment of choice is delayed exchange arthroplasty. The initial stage requires thorough debridement of all foreign material and necrotic tissue. An antibioticimpregnated cement spacer is fabricated to ease soft tissue management and enhance antibiotic delivery. The spacer is molded from Palacos cement, typically utilizing 4.8 g of tobramycin, 4.0 g of vancomycin, and 2.0 g of cefazolin mixed with 40 g of methylmethacrylate. The antibiotics chosen can be adjusted according to the sensitivities of the infecting organism, if known, and the patient's comorbidities. Typically, 28

6 weeks of intravenous antibiotics are administered, followed by observation of the patient for another 6 weeks. If persistent acute inflammation is present, then repeat debridement and spacer reimplantation are performed. When the wound has matured with resolution of swelling and erythema and return of the ESR and CRP to normal, secondstage reconstruction is undertaken. If the rotator cuff has been substantially damaged from the infection and multiple procedures, then reverse arthroplasty can be used for reconstruction.25

Glenoid Component Loosening Historically, glenoid radiolucent lines and component loosening have been frequently reported but appear to becoming less common with modern surgical techniques. Two large metaanalyses reported glenoid loosening in 5.3% to 9% of shoulders with radiolucent lines in 59%4 , 86 (Fig. 36.10). In studies with more than 10 years of follow-up, glenoid radiolucent lines were present in 79% of TSA and loosening in 34%.4 In a single series study with 15-year minimum follow-up, Sperling74 found radiolucent lines in 76% of the shoulders. The same group studied over 400 more recent replacements after 4.3 years, and only a single instance of glenoid failure was found.18 They felt complications, especially loosening, were diminishing in incidence.

29

FIGURE 36.10 Circumferential radiolucent line with medial migration of the glenoid component indicates component loosening.

A number of measures have been employed to improve glenoid fixation. All modern prosthetic systems have instrumentation designed to allow concentric reaming of the glenoid. This aids the achievement of secure seating of the component with circumferential boney support and preservation of subchondral bone. Cement pressurization further reduces radiolucent lines.64 Finally, pegged glenoid designs are associated with a lower incidence of radiolucent lines than keeled components.31 , 49 These techniques when

30

used together can dramatically decrease the incidence of radiolucent lines and ultimately loosening (Fig. 36.11). If symptomatic glenoid loosening does occur, the loss of glenoid bone stock may not allow repeat glenoid resurfacing. In 68 cases of glenoid revision reported by Cheung et al.17 insertion of another component was possible in only 35 shoulders. The glenoid was bone grafted in the remaining 38 patients. While both groups had substantial improvement in pain, clinical results were somewhat better if the glenoid could be resurfaced. Subsidence of the bone graft is common, especially for structural grafts.69 Subsequent attempts at inserting a glenoid component after the graft has healed showed only modest results, with 3 of 5 shoulders having an unsatisfactory result in one report.16

Humeral Component Loosening With an overall incidence of 1.1% to 3.6%, humeral component loosening is a clinically less significant problem than from the glenoid component.4 , 86 Radiolucent lines are still distinctly common, especially for press-fit cylindrical stems. Torchia85 noted migration of 49% of the press-fit stems after 5 years minimum follow-up and Sperling74 60% after 15 years. However, these radiographic changes are typically not associated with pain.88 Revision surgery for humeral loosening is therefore uncommon, with Chin et al.18 noting only a single revision case for combined humeral and glenoid loosening in 431 shoulder replacements. A prospective study of a tapered P.339

metaphyseal stem revealed no evidence of stem subsidence

31

or migration, although 61% of the stems showed some degree of radiolucent lines.53 Alternative methods of fixation are the use of cement or an ingrowth device. Torchia et al.85 did not find any cases of loosening of a cemented stem. Bone ingrowth may not be as reliable as cement for stem fixation, as Sperling et al.73 found 6 of 62 (9.7%) humeral stems were at risk for loosening with less than 5-year follow-up.

FIGURE 36.11 The use of modern cement technique should markedly reduce the incidence of radiolucent lines.

Glenoid Arthrosis

32

While glenoid component loosening is among the most common complications of TSA, painful glenoid arthrosis is the most frequent source of failure for HHR.4 , 8 , 9 , 13 , 66 , 75 , 86 In a systematic review of the published literature, Radnay et al.65 found 8.1% of HHRs required revision surgery to TSA due to pain. In a study of 35 HHR for osteoarthritis, Cofield et al.20 found that nine of the 35 underwent conversion to a TSA at average follow-up of 72 months. All were due to pain. Two were performed within 2 years of surgery, two between 2 to 4 years, and five at 4 or more years from the primary reconstruction. A subsequent review of 51 HHR with a minimum 5-year follow-up revealed nine (18%) required revision for painful glenoid arthrosis.66 Glenoid erosion was progressive in the remaining shoulders. In patients less than 50 years old at the time of initial surgery, Sperling et al.75 reported 15 revisions in 74 hemiarthroplasties, 11 for glenoid arthritis. Risk factors included a diagnosis of traumatic arthritis and a history of prior surgery. The pain in these patients can be severe and unrelenting, with many of the patients feeling worse off compared to their preoperative condition. The presentation is often worrisome for occult infection, which must be carefully excluded. Pain is associated with any motion, which is typically substantially restricted. The pain may never have been relieved by the HHR or may have developed in a delayed manner. Radiographs usually show complete loss of the glenohumeral joint space and frequently evidence glenoid erosion as well (Fig. 36.12). If concerns are present for substantial glenoid wear, then a CT scan should be obtained to ensure that sufficient bone stock remains for glenoid resurfacing. In theory, revision of a modular HHR to TSA is a relatively

33

straightforward process with head removal and insertion of the glenoid component. In practice, however, exposure can be difficult and typically removal of the humeral prosthesis is necessary. This may be for exposure or for malposition of the stem.41 Nevertheless, pain relief in these patients can be marked and they are frequently the most grateful of revision patients. Sperling and Cofield77 described the results in 18 shoulders with revision surgery for glenoid arthrosis. Most patients had good pain relief but motion was frequently limited. There were eight excellent, three satisfactory, and seven unsatisfactory results in their patients. The humeral component was revised in all but one of the shoulders. Carroll and associates15 reviewed 16 shoulders needing revision surgery after HHR. The authors found only three excellent results in their patients (20%), with five satisfactory (33%), and seven unsatisfactory (47%). A review of the author's experience described the results of glenoid resurfacing in 17 patients.41 There were 7 (41.2%) excellent, 5 (29.4%) satisfactory, and 5 (29.4%) unsatisfactory results. The average postoperative elevation was approximately 125 degrees. Despite the attractiveness of HHR particularly in the younger and more active patient, thus avoiding the potential failure of a glenoid component, revision surgery is complex and unsatisfactory results are disappointingly common.

34

FIGURE 36.12 This HHR was unable to relieve the patient's stiffness and pain. Loss of any glenohumeral space and undersizing of the humeral component were evident on his x-ray. Revision to a TSA with replacement of the stem relieved his pain.

Component Failure The shoulder prosthesis originally introduced by Neer was a monoblock humeral replacement. He subsequently introduced an all-polyethylene glenoid component to allow TSA.61 , 62 Since then the design of shoulder prostheses has evolved to include metal-backing of the glenoid component, in-growth glenoid components, modular humeral heads, and reverse designs. The increased complexity of these designs has

35

introduced new potential methods of failure for shoulder arthroplasty. Blevins et al.3 has reported occurrences of dissociation of a modular titanium head from the stem through failure of the Morse taper. He identified 13 cases of this complication and calculated an incidence of approximately 1:1000 for that prosthesis. Two important points were emphasized. Investigation revealed that as little as 0.4 mL of fluid contamination of the Morse taper interfered with solid fixation. Additionally, 12 of the 13 cases of disassembly occurred within the first 6 weeks after surgery. This suggested problems with the taper lock in manufacturing potentially and emphasizes the need to ensure that a secure lock is established at surgery. Component failure and dissociation remain a current issue and are seen in reverse systems (Fig. 36.13A,B). Particulate debris from polyethylene or metal wear can stimulate synovitis and osteolysis as well. Wallace noted that an uncemented glenoid could be associated with eccentric wear of the posterior metal rim and osteolysis, but this process is not unique to one prosthetic design.91 Sperling and Cofield79 described one case of particulate synovitis associated with instability in a series of 18 revision arthroplasties. Gartsman et al.32 found a single instance of titanium synovitis in 100 consecutive replacements with a Biomet prosthesis. Klimkiewicz et al.47 described a case report of humeral loosening associated with osteolysis. His analysis suggested that late subsidence of the humeral component resulted in a degree of mechanical instability in the reconstruction. P.340

36

The instability resulted in accelerated polyethylene wear, with subsequent osteolysis and ultimately loosening of the component.

FIGURE 36.13 This reverse replacement initially functioned well, and postoperative x-rays were felt satisfactory (A). Four months postoperatively, the patient noted the development of pain and loss of motion. The glenosphere had dislodged from the metaglenoid (B).

It seems clear then that the increased complexity of prosthetic designs introduces additional potential problems. Any metal-backed glenoid component raises the possibility of metal on metal wear if the polyethylene fails and all modular components have the potential for disassembly. The chances of these problems appear to be increased with any degree of instability in the reconstruction, which can cause accelerated wear of the polyethylene surface even with a nonmodular glenoid component. Particulate synovitis and osteolysis can 37

result, although the incidence seems low. Nevertheless, it is part of the differential diagnosis for the painful shoulder replacement.

Neurologic Deficit Although a problem rarely needing surgery, postoperative neurologic problems can provoke considerable distress for both the patient and physician. Lynch et al.52 found 18 cases of postoperative neurologic deficit after 417 shoulder replacements in 368 patients (4%) at the Mayo Clinic. Thirteen of the lesions were brachial plexopathies, primarily upper and middle trunk lesions. In addition, there were three instances of idiopathic brachial plexopathy felt secondary to brachial neuritis, and one patient had persistence of a preexisting plexopathy. Finally, a single patient developed carpal tunnel syndrome. Patients at higher risk for these problems were those who were taking methotrexate, had an extended deltopectoral approach for exposure over an anteromedial approach, and had shorter operative times. Many factors were found to have no relationship to neurologic complications. These included age of patient, sex, diagnostic category, height, weight, range of motion, prior surgery, rotator cuff tearing, and the presence of diabetes or rheumatoid arthritis. The outcome of the deficits was fairly good, with 11 of the patients followed at 1 year having a good result and five a fair recovery. Only in four of the patients was the rehabilitative program altered by the nerve injury. The etiology of the neurologic deficits was felt to be primarily traction.52 The performance of shoulder arthroplasty involves placing the extremity into various positions of extension and rotation to expose the humeral canal. This manipulation

38

places stress across the brachial plexus, and this stress can be increased through poor positioning of the head. Early in our experience with shoulder replacement, a standard operative table was utilized. Access to the shoulder involved rotation and tilting the cervical spine away from the operative site. This can place addition forces across the plexus and potentially lead to an injury. More recently, use of a table modification allows placement of the head in a neutral position. One option is the utilization of a Mayfield head frame. This eases access to the humeral canal in conjunction with lateralization of the patient. Alternatively, table attachments are available for shoulder surgery allowing removal of the upper quadrant of the table. Access to the posterior aspect of the shoulder is particularly improved, but support of the thorax is diminished and obese patients are often unstable in these setups. It is up to the surgeon to decide which arrangement works best in his or her hands. Either situation offers the potential for diminishment of the forces across the plexus and reduction of the incidence of neurologic injuries.

Stiffness The ultimate range of motion after shoulder arthroplasty can be related to factors beyond the surgeon's control such as the diagnostic group, status of the rotator cuff, and overall condition of the patient.23 , 28 Other factors, however, are under the physician's influence and include the degree of capsular P.341 release, component positioning, and head selection.28 , 37

39

Failure to achieve a degree of motion appropriate to the diagnosis is a complication of surgery and is a leading cause of patient dissatisfaction.38 Stiffness can also be a presenting symptom of other complications, such as infection, component loosening, or glenoid arthrosis. These problems must be specifically looked for, and corrected if present. The evaluation of inadequate motion includes review of the preoperative radiograph, the operative report, presenting range of motion, and current radiographs. The preoperative xray is reviewed for factors that could influence reconstruction and motion. For example, superior subluxation of the humeral head can suggest an incompetent rotator cuff, posterior subluxation may indicate a patulous posterior capsule associated with anterior contracture perhaps compensated for with an oversized humeral head, and posttraumatic changes commonly are found with circumferential scarring. The operative report allows insight into how these issues were addressed. Physical examination is performed to evaluate the specific directions of restricted motion and function of the rotator cuff. The areas of stiffness will give direction to the releases necessary, although the final decisions are made intraoperatively with the trial prostheses in place. Finally, the current x-rays films are reviewed for evidence of component malposition and overstuffing of the joint. Humeral head position should be at or slightly superior to the tip of the greater tuberosity, with the humeral osteotomy typically made just inside the rotator cuff insertion. A high cut can lead to a proud component producing overtensioning of the supraspinatus or superior impingement. In addition, the uncovered calcar can abut the glenoid and block adduction. Inappropriate version may be related to instability, possibly

40

compensated with a larger head size. A large head size will place abnormal stress on the cuff and limit motion. Harryman et al.37 studied the influence of the head size on range of motion in eight cadaveric shoulders. He found use of a 5-mm oversized head was associated with a marked decrease in motion ranging from 23% to 30% in elevation, flexion, and rotation. He also demonstrated the increase in tension on soft tissues by seating an anatomic head in a proud position. Figgie et al.28 similarly noted that use of an enlarged head was related to diminished results and, conversely, restoration of normal glenoid and humeral anatomy with improved results. Initial capsular releases are chosen based on the preoperative physical examination and the prosthesis revised if malpositioned. It may be that only the head size needs to be changed or just soft tissue work is necessary. With an appropriate head trial in place, final decision can be made on soft tissue releases if these have not already been performed as part of the exposure. When there is loss of external rotation to less than a minimum of 30 to 40 degrees, the anterior capsule and subscapularis need to be lengthened. This is best accomplished by circumferential mobilization of the subscapularis from all adhesions including along the glenoid margin. Advancement of the subscapularis to the edge of the humeral osteotomy and lengthening by z-plasty are alternative options but may result in a weaker repair.21 If internal rotation to 120 degrees is not obtainable, then release of the posterior capsule along the glenoid margin should be considered.21 , 28 Additional sources of stiffness include impingement at a retained humeral neck, excessive lateral offset from a large humeral head, or malposition of the

41

head in increased retroversion. Blockage of abduction below 160 degrees is most common from constricted inferior and posterior capsule. Release of the inferior capsule along the humeral neck can be safely carried out to the 6 o'clock position, but if further release is necessary, it is wise to identify and protect the axillary nerve as the release is directed toward the posterior inferior aspect of the glenoid.21 Less commonly superior release is necessary when there is circumferential scarring around the joint.

Thrombo-embolic Disease Shoulder arthroplasty patients are not immune to thromboembolic events. Analyzing a New York State medical database, Lyman et al.51 found that the incidence of deep venous thrombosis was 5 per 1000 patients and that of pulmonary embolus 2.3 per 1000. Risk factors were increasing age, a history of trauma, and cancer. Sperling and Cofield76 looked at 2885 consecutive cases of primary shoulder arthroplasty and identified 5 cases of pulmonary embolus. All were nonfatal, but symptoms in three of the five were initially attributed to other causes. While there is no consensus on the precise type of prophylaxis, clearly it is prudent to utilize some antithrombolic measure for shoulder replacement patients. Most importantly, surgeons must be aware these events do occur and evaluate patients' symptoms appropriately.

Heterotopic Ossification Heterotopic ossification (HO) is a frequent finding on postoperative radiographs that can be easily overlooked.26 , 45 , 78 , 93 Fortunately, it usually is of limited consequence. Sperling and Cofield78 have outlined a grading

42

system that allows the extent of the ectopic bone to be described. In Grade 0, there is no bone evident. In Grade I, the excess bone bridges less than 50% of the distance between the lateral aspect of the glenoid and the medial cortex of the humeral shaft or the acromion. If over 50% is ossified, it is classified as Grade II disease. Finally, in Grade III, there is an osseous bridge. In a study of 58 primary ingrowth TSA, heterotopic bone was found in 14 cases (24.1%).78 Twelve were Grade I and two were Grade II. No identifiable patient characteristics were detected, including diagnosis, sex, age, need for bone grafting, prior surgery, and rotator cuff tearing. In addition, the outcome as determined by range of motion, pain relief, and overall result was not influenced by the presence of the heterotopic bone. Their conclusion was that the process is usually low grade, present within 1 to 2 months on x-ray, does not progress, and does not affect the result. Similarly, Moeckel et al.57 found 9 cases of HO out of 22 cases of HHR for proximal humeral fractures, but no correlation with result. Kjaersgaard-Anderson et al.45 detected HO in 26 of 58 TSA after 1-year follow-up. Bridging bone was found in 6 (10%). He did find a higher incidence in male patients and in osteoarthritis, but no influence on pain relief and no difference in incidence with use of nonsteroidal anti-inflammatory drugs. The shoulders with Grade III HO did evidence diminished range of motion. Thus, HO is a frequent finding on postoperative radiographs, but in almost all cases, little note needs to be taken of the process and indications for removal of the bone are rare.

REVERSE SHOULDER ARTHROPLASTY

43

Reverse shoulder arthroplasty was approved for use in this country by the Food and Drug Administration in 2004, and its popularity has rapidly increased. The incidence of P.342

complications with reverse is clearly higher than with the more established anatomic designs of shoulder arthroplasty.5 , 93 , 94 A portion of the higher complication rate may be attributed to the learning curve associated with the introduction of new technology.40 , 94 Wierks reported a higher intraoperative complication rate in their initial 10 patients and Hattrup a higher reoperation rate in his first 25 patients with a reverse shoulder system.

44

FIGURE 36.14 This reverse replacement demonstrates both inferior scapular notching as well as an acromial fracture. This was suffered 1 year post-operatively when the patient fell.

Scapular notching exemplifies the role of increased experience and understanding of this procedure plays in its complication rate. Presumptively caused by mechanical impingement of the humeral metaphysis on the scapula, notching is found in the majority of shoulder in some series5 , 50 , 70 , 87 (Fig. 36.14). Boileau et al.5 reported some degree of notching in 68% in his series. Simovitch et al.70 found not only additional notching did not appear after 14

45

months but also that notching could be reduced or prevented by optimal positioning of the glenoid component inferiorly on the glenoid surface. Reverse arthroplasty is also associated with relatively higher rates of hematoma formation, glenohumeral dislocation, acromial fracture, component disassociation, and infection5 , 71 , 90 , 92 , 93 (Fig. 36.14). Werner et al.93 reported a 50% complication rate and 33% reoperation rate in a series of 58 Grammont type of reverse arthroplasties after only 38months follow-up and Boileau et al.5 a 34% incidence of complication in 45 cases. Werner et al.93 found the most common complications were hematoma formation in almost 21% of shoulders and dislocation in 8.6%. In a series of 191 cases, Wall reported a 7.8% rate of dislocation and 4.2% incidence of infection.92 Complications are less frequent in the primary reverse replacement versus a revision shoulder arthroplasty.92 , 93 The high incidence of complication and revision surgery has led to high reported failure rates. In a survivorship analysis at 8 years, Sirveaux et al.71 found prosthetic failure from loosening or pain occurred in over 70% of shoulders. Although newer designs of reverse replacements have been introduced by various manufacturers, substantiation of improved prosthetic survival in peer-reviewed literature remains lacking. Until then, surgeons should generally restrict the use of these devices to the elderly patient.

References 1. Barrett WP, Franklin JL, Jackins S, et al: Total shoulder arthroplasty. J Bone Joint Surg 69-A:865-872, 1987.

46

2. Barrett WP, Thornhill TS, Thomas WH, et al: Nonconstrained total shoulder arthroplasty in patients with polyarticular rheumatoid arthritis. J Arthroplasty 4:91-96, 1989. 3. Blevins FT, Deng X, Torzilli PA, et al: Dissociation of modular humeral head components: A biomechanical and implant retrieval study. J Shoulder Elbow Surg 6:113-124, 1997. 4. Bohsali KI, Wirth MA, Rockwood CA Jr: Complications of total shoulder arthroplasty. J Bone Joint Surg 88-A:22792292, 2006. 5. Boileau P, Watkinsom D, Hatzidakis AM, Hovorka I: The Grammont reverse shoulder prosthesis: Results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15(5):527-540, 2006. 6. Bonutti PM, Hawkins RJ: Fracture of the humeral shaft associated with total replacement arthroplasty of the shoulder. J Bone Joint Surg 74-A:617-618, 1992. 7. Boyd AD Jr, Aliabadi P, Thornhill TS: Postoperative proximal migration in total shoulder arthroplasty. Incidence and significance. J Arthroplasty 6:31-37, 1991. 8. Boyd AD, Thomas WH, Scott RD, et al: Total shoulder arthroplasty versus hemiarthroplasty. Indications for glenoid resurfacing. J Arthroplasty 5:329-336, 1990. 9. Boyd AD, Thomas WH, Sledge CB, Thornhill TS: Failed shoulder arthroplasty (abstract). Orthop Trans 14:255, 1990. 10. Boyd RL, Thornhill TS, Barnes CL: Fractures adjacent to humeral prostheses. J Bone Joint Surg 74-A:1498-1504, 1992.

47

11. Braman JP, Sprague M, Bishop J, et al: The outcome of resection shoulder arthroplasty for recalcitrant shoulder infection. J Shoulder Elbow Surg 15(5):549-553, 2006. 12. Brenner BC, Ferlic DC, Clayton ML, Dennis DA: Survivorship of unconstrained total shoulder arthroplasty. J Bone Joint Surg 71-A:1289-1296, 1989. 13. Broström L-Å, Kronberg M, Wallensten R: Should the glenoid be replaced in shoulder arthroplasty with an unconstrained Dana or St. George Prosthesis? Annales Chir et Gyn 81:54-57, 1992. 14. Campbell JT, Moore RS, Iannotti JP, et al: Periprosthetic humeral fractures: mechanism of fracture and treatment options (abstract). J Shoulder Elbow Surg 6:176, 1997. 15. Carroll RM, Izquierdo R, Vazquez M, et al: Conversion of painful hemiarthroplasty to total shoulder arthroplasty: longterm results. J Shoulder Elbow Surg 13:599-603, 2004. 16. Cheung EV, Sperling JW, Cofield RH: Reimplantation of a glenoid component following component removal and allogenic bone grafting. J Bone Joint Surg 89-A:1777-1783, 2007. 17. Cheung EV, Sperling JW, Cofield RH: Revision shoulder arthroplasty for glenoid component loosening. J Shoulder Elbow Surg 17(3):371-375, 2008. 18. Chin PYK, Sperling JW, Cofield RH, Schleck C: Complications of total shoulder arthroplasty: Are they fewer or different? J Shoulder Elbow Surg 15(1):19-22, 2006. 19. Cofield RH, Edgerton BC: Total shoulder arthroplasty: Complications and revision surgery. Instr Course Lect 39:449, 1990.

48

20. Cofield RH, Frankle MA, Zuckerman JD: Humeral head replacement for glenohumeral arthritis. Semin Arthroplasty 6:214-221, 1995. 21. Cofield RH: Integral surgical maneuvers in prosthetic shoulder arthroplasty. Semin Arthroplasty 1:112-123, 1990. 22. Cofield RH: Revision procedures for shoulder arthroplasty, vol 1. In Morrey BF (ed): Reconstructive Surgery of the Joints. New York, Churchill Livingstone, 1996, p. 789. 23. Cofield RH: Total shoulder arthroplasty with the Neer prosthesis. J Bone Joint Surg 66-A:899-906, 1984. 24. Coste JS, Reig S, Trojani C, et al: The management of infection in arthroplasty of the shoulder. J Bone Joint Surg 86-B:65-69, 2004. P.343

25. Cuff DJ, Virani NA, Levy J, Frankle MA, et al: The treatment of deep shoulder infection and glenohumeral instability with debridement, reverse shoulder arthroplasty, and post-operative antibiotics. J Bone Joint Surg 90-B:36-42, 2008. 26. Dines DM, Warren RF, Altchek DW, Moeckel B: Posttraumatic changes of the proximal humerus: Malunion, nonunion, and osteonecrosis. Treatment with modular hemiarthroplasty or total shoulder arthroplasty. J Shoulder Elbow Surg 2:11-21, 1993. 27. Field LD, Dines DM, Zabinski SJ, Warren RF: Hemiarthroplasty of the shoulder for rotator cuff arthropathy. J Shoulder Elbow Surg 6:18-23, 1997. 28. Figgie HE III, Inglis AE, Goldberg VM, et al: An analysis of factors affecting the long-term results of total shoulder

49

arthroplasty in inflammatory arthritis. J Arthroplasty 3:123130, 1988. 29. Franklin JL, Barrett WP, Jackins SE, Matsen FA III: Glenoid loosening in total shoulder arthroplasty: Association with rotator cuff deficiency. J Arthroplasty 3:39-46, 1988. 30. Galatz LM, Conner PM, Calfee RP, et al: Pectoralis major transfer for anterior-superior subluxation in massive rotator cuff insufficiency. J Shoulder Elbow Surg 12(1):1-5, 2003. 31. Gartsman GM, Roddey TS, Hammerman SM: Shoulder arthroplasty with or without resurfacing of the glenoid in patients who have osteoarthritis. J Bone Joint Surg 82-A:2634, 2000. 32. Gartsman GM, Russell JA, Gaenslen E: Modular shoulder arthroplasty. J Shoulder Elbow Surg 6:333-339, 1997. 33. Gill DRJ, Cofield RH, Morrey BF: Ipsilateral total shoulder and elbow arthroplasties in patients who have rheumatoid arthritis. J Bone Joint Surg 81-A:1128-1137, 1999. 34. Groh GI, Heckman MM, Curtis RJ, Rockwood CA Jr: Treatment of fractures adjacent to humeral prosthesis (abstract). Orthop Trans 18:1072, 1994-5. 35. Groh GI, Heckman MM, Wirth MA, et al: Treatment of fractures adjacent to humeral prostheses. J Shoulder Elbow Surg 17:85-89, 2008. 36. Groh GI, Simoni M, Rolla P, Rockwood CA Jr: Loss of the deltoid after shoulder operations: an operative disaster. J Shoulder Elbow Surg 3: 243-253, 1994. 37. Harryman DT, Sidles JA, Harris SL, et al: The effect of articular conformity and the size of the humeral head component on laxity and motion after glenohumeral arthroplasty. J Bone Joint Surg 77-A:555-563, 1995.

50

38. Hasan SS, Leith JM, Campbell B, et al: Characteristics of unsatisfactory shoulder arthroplasty. J Shoulder Elbow Surg 11(5):431-441, 2002. 39. Hattrup SJ, Cofield RH, Cha SS: Rotator cuff repair after shoulder replacement. J Shoulder Elbow Surg 15(1):78-83, 2006. 40. Hattrup SJ: Early complications with the Delta reverse shoulder arthroplasty: Influence of the learning curve. J Shoulder Elbow Surg 16(2):e55, 2007. 41. Hattrup SJ: Revision total shoulder arthroplasty for painful humeral head replacement with glenoid arthrosis. J Shoulder Elbow Surg 18(2):220-224, 2009. 42. Hawkins RJ, Bell RH, Jallay B: Total shoulder arthroplasty. Clin Orthop Relat Res 242:188-194, 1989. 43. Hawkins RJ, Greis PE, Bonutti PM: Treatment of symptomatic glenoid loosening following unconstrained shoulder arthroplasty. Orthopedics 22:229-234, 1999. 44. Ince A, Seemann K, Frommelt L, et al: One-stage exchange shoulder arthroplasty for peri-prosthetic infection. J Bone Joint Surg 87-B:814-818, 2004. 45. Kjaersgaard-Anderson P, Frich LH, Søjbjerg JO, Sneppen O: Heterotopic bone formation following total shoulder arthroplasty. J Arthroplasty 4:99-104, 1989. 46. Kligman M, Roffman M: Humeral fracture following shoulder arthroplasty. Orthopedics 22:511-513, 1999. 47. Klimkiewicz JJ, Iannotti JP, Rubash HE, Shanbag AS: Aseptic loosening of the humeral component in total shoulder arthroplasty. J Shoulder Elbow Surg 7:422-426, 1999. 48. Kozak TKW, Hanssen AD, Cofield RH: Infected shoulder arthroplasty. J Shoulder Elbow Surg 6:177, 1997.

51

49. Lazarus MD, Jensen KL, Southworth C, Matsen III FA: The radiographic evaluation of keeled and pegged glenoid component insertion. J Bone Joint Surg 84-A:1174-1182, 2002. 50. Levigne C, Boileau P, Favard L, et al: Scapular notching in reverse shoulder arthroplasty. J Shoulder Elbow Surg 17(6):925-935, 2008. 51. Lyman S, Sherman S, Carter TI, et al: Prevalence and risk factors for symptomatic thromboembolic events after shoulder arthroplasty. Clin Orthop Relat Res 448:152-156, 2006. 52. Lynch NM, Cofield RH, Silbert PL, Hermann RC: Neurologic complications after total shoulder arthroplasty. J Shoulder Elbow Surg 5: 53-61, 1996. 53. Matsen FA III, Iannotti JP, Rockwood CA Jr: Humeral fixation by pressfitting of a tapered metaphyseal stem 85A:304-308, 2003. 54. Miller BS, Joseph TA, Noonan TJ, et al: Rupture of the subscapularis tendon after shoulder arthroplasty: diagnosis, treatment, and outcome. J Shoulder Elbow Surg 14:492-496, 2005. 55. Miller SL, Hazrati Y, Klepps S, et al: Loss of subscapularis function after total shoulder replacement: A seldom recognized problem. J Shoulder Elbow Surg 12(1):2934, 2003. 56. Moeckel BH, Altcheck DW, Warren RF, et al: Instability of the shoulder after arthroplasty. J Bone Joint Surg 75-A:492497, 1993. 57. Moeckel BH, Dines DM, Warren RF, Altchek DW: Modular hemiarthroplasty for fractures of the proximal part of the humerus. J Bone Joint Surg 74-A:884-889, 1992.

52

58. Neer CS II, Brown TH Jr, McLaughlin HL: Fractures of the neck of the humerus with dislocation of the head fragment. Am J Surg 85:252-258, 1953. 59. Neer CS II, Kirby RM: Revision of humeral head and total shoulder arthroplasties. Clin Orthop Relat Res 170:189-195, 1982. 60. Neer CS II, Morrison DS: Glenoid bone grafting in total shoulder arthroplasty. J Bone Joint Surg 70-A:1154-1162, 1988. 61. Neer CS II, Watson KC, Stanton FJ: Recent experience in total shoulder replacement. J Bone Joint Surg 64-A:319-337, 1982. 62. Neer CS II: Replacement arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg 56-A:1-13, 1974. 63. Norris TR, Lipson SR: Management of the unstable prosthetic shoulder. Instr Course Lect 47:141, 1998. 64. Nyffeler RW, Meyer D, Sheileh R, et al. The effect of cementing technique on structural fixation of pegged glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 15(1):106-111, 2006. 65. Radnay CS, Setter KJ, Chambers L, et al: Total shoulder replacement compared with humeral head replacement for the treatment of primary glenohumeral osteoarthritis: A systematic review. J Shoulder Elbow Surg 16:396-402, 2007. 66. Rispoli DM, Sperling JW, Athwal GS, et al: Humeral head replacement fir the treatment of osteoarthritis. J Bone Joint Surg 88-A:2637-2644, 2006. 67. Rodosky MW, Bigliani LU: Indications for glenoid resurfacing in shoulder arthroplasty. J Shoulder Elbow Surg 5:231-248, 1996.

53

68. Sanchez-Sotelo J, Sperling JW, Rowland CM, Cofield RH: Instability after shoulder arthroplasty: Results of surgical treatment. J Bone Joint Surg 85-A:622-631, 2003. 69. Scalise JJ, Iannotti JP: Bone grafting severe glenoid defects in revision shoulder arthroplasty. Clin Orthop Relat Res 466:139-145, 2008. 70. Simovitch RW, Zumstein MA, Lohri E, et al: Predictors of scapular notching in patients managed with the Delta III reverse total shoulder replacement. J Bone Joint Surg 89A:588-600, 2007. 71. Sirveaux F, Favard L, Oudet D, et al: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. J Bone Joint Surg 86-B:388-395, 2004. 72. Søjbjerg JO, Frich LH, Johannsen HV, Sneppen O: Late results of total shoulder replacement in patients with rheumatoid arthritis. Clin Orthop Relat Res 366:39-45, 1999. 73. Sperling JW, Cofield RH, O'Driscoll SW, et al: Radiographic assessment of ingrowth total shoulder arthroplasty. J Shoulder Elbow Surg 9(6):507-513, 2000. 74. Sperling JW, Cofield RH, Rowland CM: Minimum fifteenyear follow-up of Neer hemiarthroplasty and total shoulder arthroplasty in patients aged fifty years or younger. J Shoulder Elbow Surg 13(6):604-613, 2004. 75. Sperling JW, Cofield RH, Rowland CM: Neer hemiarthroplasty and Neer total shoulder arthroplasty in patients fifty years old or less. J Bone Joint Surg 80-A:464473, 1998. 76. Sperling JW, Cofield RH: Pulmonary embolism following shoulder arthroplasty. J Bone Joint Surg 84-A:1939-1941, 2002.

54

77. Sperling JW, Cofield RH: Revision total shoulder arthroplasty for the treatment of glenoid arthrosis. J Bone Joint Surg 80-A:860-867, 1998. 78. Sperling JW, Cofield RH, Rowland CM: Heterotopic ossification after total shoulder arthroplasty. J Arthroplasty 15:179-182, 2000. 79. Sperling JW, Cofield RH: Revision total shoulder arthroplasty for the treatment of glenoid arthrosis. J Bone Joint Surg 80-A:860-867, 1998. 80. Sperling JW, Potter HG, Craig EV, et al: Magnetic resonance imaging of painful shoulder arthroplasty. J Shoulder Elbow Surg 11(4):315-321, 2002. 81. Steinman SP, Cheung EV: Treatment of periprosthetic humerus fractures associated with shoulder arthroplasty. J Am Acad Orthop Surg 16(4):199-207, 2008. 82. Stewart MPM, Kelly IG: Total shoulder replacement in rheumatoid disease. J Bone Joint Surg 79-B:68-72, 1997. 83. Strickland JP, Sperling JW, Cofield RH: The results of two-stage reimplantation for infected shoulder replacement. J Bone Joint Surg 90-B:460-465, 2008. 84. Topolski MS, Chin PYK, Sperling JW, Cofield RH: Revision shoulder arthroplasty with positive intraoperative cultures: The value of preoperative studies and intraoperative histology. J Shoulder Elbow Surg 15(4):402-406, 2006. 85. Torchia ME, Cofield RH, Settergren CR: Total shoulder arthroplasty with the Neer prosthesis: Long-term results. J Shoulder Elbow Surg 6:495-505, 1997. 86. Van de Sande MAJ, Brand R, Rozing PM: Indications, complications, and results of shoulder arthroplasty. Scand J Rheum 35:426-434, 2006.

55

87. Vanhove B, Beugnies A: Grammont's reverse shoulder prosthesis for rotator cuff arthropathy. A retrospective study of 32 cases. Acta Orthop Belg 70:219-225, 2004. P.344

88. Verborgt O, El-Abiad R, Gazielly DF: Long term results of uncemented humeral components in shoulder arthroplasty. J Shoulder Elbow Surg 16(3S):13S-18S, 2007. 89. Walch G, Boileau P: Prosthetic adaptability: A new concept for shoulder arthroplasty. J Shoulder Elbow Surg 8:443-451, 1999. 90. Wall B, Nove-Josserand L, O'Connor DP, et al: Reverse total shoulder arthroplasty: A review of results according to etiology. J Bone Joint Surg 89-A:1476-1485, 2007. 91. Wallace AL, Phillips RL, MacDougal GA, et al: Resurfacing of the glenoid in total shoulder arthroplasty. J Bone Joint Surg 81-A:510-518, 1999. 92. Weissinger M, Helmreich C, Teumann E: Initial experience using the inverse prosthesis of the shoulder. Acta Chir Orthop Traumatol Cech 75:21-32, 2008. 93. Werner CML, Steinmann PA, Gilbart M, Gerber C: Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total shoulder prosthesis. J Bone Joint Surg 85-A:1476-1486, 2005. 94. Wierks C, Skdasky RL, Ji JH, McFarland EG: Reverse total shoulder arthroplasty. Intraoperative and early postoperative complications. Clin Orthop Relat Res 467(1): 225-234, 2009.

56

95. Wiley AM: Superior humeral dislocation. A complication following decompression and debridement for rotator cuff tears. Clin Orthop Relat Res 263:135-141, 1991. 96. Wirth MA, Rockwood CA: Complications of total shoulder arthroplasty. Clin Orthop Relat Res 307:47-69, 1994. 97. Wirth MA, Rockwood CA: Complications of total shoulderreplacement arthroplasty. J Bone Joint Surg 78-A:603-616, 1996. 98. Worland RL, Arredondo J: Bipolar shoulder arthroplasty for painful conditions of the shoulder. J Arthroplasty 13:631637, 1998. 99. Worland RL, Kim Do Yung: Periprosthetic humeral fractures: Management and classification. J Shoulder Elbow Surg 8:590-594, 1999. 100. Wright TW, Cofield RH: Humeral fractures after shoulder arthroplasty. J Bone Joint Surg 77-A:1340-1346, 1995. 101. www.aaos.org/Research/stats/Joint%20Replacments%20from %20Head%20to%20toe.pdf

57

Chapter 37 Radiographic Assessment of Painful Shoulder Arthroplasty Eric A. Bogner Edward V. Craig A painful shoulder following arthroplasty is among the most difficult and challenging evaluation and management problems for the clinician. The evaluation of the patient with a painful shoulder arthroplasty typically begins with a complete assessment of the patient's record, including operative reports, to gain an understanding of the indication for which the index arthroplasty was performed. As with all orthopaedic conditions, a careful history of the past and current conditions of the shoulder, in combination with a directed physical exam, is fundamental. Evaluation of both passive and active range of motion, strength, and a comprehensive neurovascular examination all begin to direct the surgeon to potential causes of the shoulder pain. Aspiration and culture as well as systemic blood tests such as sedimentation rate and Creactive protein may help answer the question of prosthetic infection. As shoulder arthroplasty has evolved and continued to grow over the last 40 years, radiology, in various modalities, has been instrumental in attempting to uncover the precise causes of the painful arthroplasty. There has been a 40% increase in the number of annual shoulder arthroplasties done from 1990 to 1992 as compared to 1996-2002.13 In that same time span, advances have occurred in radiology, particularly involving computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI).

1

IMAGING MODALITIES Radiography The primary imaging modality still employed for evaluation of a shoulder arthroplasty is a plain radiograph (Figs. 37.1, 37.2, 37.3, 37.4 and 37.5). Plain radiography is a helpful modality to assist in evaluating for septic or aseptic component loosening, instability, and nonunion or malunion of tuberosities. It is also helpful to assess bone quality and bone loss as well as nonglenohumeral causes of pain such as acromioclavicular arthritis, acromial spurs associated with rotator cuff impingement, calcium within the rotator cuff tendon, and postoperative heterotopic bone. The most common postoperative views are the Grashey view or 40-degree posterior oblique view with the affected limb held in external rotation and an AP view with the forearm held in internal rotation. If there are concerns as related to subluxation or dislocation, a tangential view, either scapulars “Y” view or axillary view, is helpful. The expected anatomic positioning of an unconstrained prosthesis is the humeral head situated approximately 5 mm superior to the greater tuberosity and humeral retroversion of 30 to 40 degrees.11 , 19 The humeral prosthesis should be parallel to the cut surface of the neck.1 The glenoid component should be well centered, and a variable degree of postoperative periprosthetic lucency has been reported in the literature.

Magnetic Resonance Imaging The most commonly employed advanced modality for imaging the painful prosthesis at our institution is MRI. MRI in the setting of shoulder arthroplasty is difficult because of the

2

inherent magnetic inhomogeneities from the implant but also secondary to the orientation of the orthopaedic hardware. The shoulder arthroplasty is asymmetrically situated in the scanner, precipitating a greater degree of artifact than seen with a hip or knee arthroplasty.29 As is the case with other types of arthroplasty, the MRI imaging parameters need to be changed from the routine in order to obtain diagnostic images. The limiting step in the evaluation of hardware with MRI is that highly magnetized structures (ferromagnetic) and slightly less magnetized structures (diamagnetic) distort the local magnetic field, induce local gradients, and cause a mismapping or misregistration of signal, causing focal areas of blackness (signal void) and brightness (bright signal or flare).26 , 33 This becomes crucial to the orthopaedic surgeon in that one can predict based on the metal used for the arthroplasty, the overall degree of diagnostic acumen of the MRI. As it relates to the modifications employed in the setting of arthroplasty, rudimentary knowledge is paramount, as the orthopaedic surgeon can work in concert with the radiologist to P.346

produce the best images possible and understand the limitations of the examination. MRI is complicated but the field of view (horizontal and transverse) is split into a frequency- and phaseencoded direction, both of which have a gradient strength. It has been found that by choosing the frequency-encoded direction along the long axis of the component and increasing the frequency gradient, there is a reduction in the misregistration artifact.7 , 35 In all MRI of an

3

arthroplasty, a fat-suppressed sequence should be obtained to assess for gross phenomenon such as a large joint effusions, soft tissue collection, or periprosthetic fracture. There are multiple ways that this can be performed in the routine MRI, but in the setting of hardware, only the inversion recovery sequence is able to yield a homogeneous fat suppression in the setting of inhomogeneities from the implemented metal. Frequency-selective fat suppression should not be utilized as it will yield poor fat suppression in this setting.7 , 35 Another pulse sequence that is frequently used in orthopaedic imaging is gradient echo sequencing. These should not be employed in the setting of a total joint arthroplasty as these pulse sequences yield large areas of blackness (signal void) secondary to the lack of a refocusing pulse and subsequent intravoxel dephasing.35 Other factors are involved but are beyond the scope of basic knowledge and include a longer readout bandwidth than typically utilized (our institution uses 62.5 kHz), fast spin-echo imaging with decreased interecho spacing, and a long echo train length.26

4

FIGURE 37.1 Plain radiography of a hemiarthroplasty inserted for a proximal humeral fracture with a high riding humeral component, secondary arthritis of the glenoid, and humeral subsidence.

5

FIGURE 37.2 A painful total shoulder replacement inserted for primary osteoarthritis. Incomplete humeral head resection, including residual osteophytes, has resulted in “overstuffing” the joint. The humeral component has been superiorly resulting in increased contact with the superior glenoid component and subsequent loosening.

6

FIGURE 37.3 The patient was revised to a total shoulder replacement by implant removal of the humerus, recutting the humerus at an appropriate position, and exchanging the glenoid component. Note the centered position of the humeral head on the new glenoid component.

7

FIGURE 37.4 A plain radiograph axillary view of a reverse shoulder arthroplasty, showing component dislocation from the glenosphere, loosening of the humeral stem, and a periprosthetic fracture. Revision in this setting is extremely challenging.

8

FIGURE 37.5 A: AP view of a TSA with expected positioning of components. Note the humeral prosthesis well situated across from the glenoid component. B: Grashey view of a reverse prosthesis in expected position with flush position of the baseplate to the native glenoid.

MRI is exquisite in showing soft tissue abnormalities, commonly a problem in the painful shoulder arthroplasty, specifically subscapularis and supraspinatus tears, glenoid cartilage wear, and muscle quality (Fig. 37.6).29 Additionally, as has been proven by Walde et al., osteolysis is most accurately displayed with MRI, yielding 95% sensitivity, 98% specificity, and 96% accuracy. This is in comparison to a sensitivity of 52% in radiographs and 75% in CT. However, this assumes that the technique is performed in an appropriate manner and the interpreting radiologist is skilled in diagnosis in the setting of total joint arthroplasty.32 Potter et al. clearly showed that P.347

osteolysis can be identified on MRI, with signal characteristics differing particularly from infection. The characteristic findings will be described later in this chapter.21 Because it is unsurpassed in evaluating soft tissue, less common causes of pain such as cement extrusion and/or compression of nerve may be identified with MRI.

9

FIGURE 37.6 A: Axial MRI showing posterior positioning of the humeral component (H) and absence of the normal grey cartilage (white arrows) along the glenoid surface on this proton density axial sequence. Also note the relative preservation of posterior glenoid bone stock at this time. B: Coronal MRI showing preservation of the supraspinatus with the tendon seen attaching to the greater tuberosity (Muscle belly delineated by white arrows and tendon by block arrow).

Musculoskeletal Ultrasound Musculoskeletal ultrasound has gained in popularity over the last 15 years and is a valuable adjunct in the setting of the painful shoulder arthroplasty. Typically shoulder ultrasounds are performed using a medium-frequency, linear transducer to adequately evaluate the deeper structures of the shoulder.22 While MRI is an excellent resource for the evaluation of a shoulder arthroplasty, it is not always available either due to patient contraindications (pacemaker, neurostimulator, etc.), patient intolerance such as claustrophobia, or cost. Ultrasound is able to demonstrate the integrity of the rotator cuff tendons and musculature, fluid collections in suspected 10

infection, and particle wear as delineated by punctuate, bright, or echogenic foci scattered throughout the joint (Fig. 37.7).25

Nuclear Medicine (Scintigraphy) Another frequently used modality in the workup of the painful shoulder arthroplasty is nuclear medicine imaging or scintigraphy. The role of bone scans has been well established in other total joint arthroplasties, specifically the hip and knee. Given the relative lower incidence of shoulder arthroplasty compared to hip and knee arthroplasty, there is not extensive literature available on the outcome of this imaging modality. Nonetheless, scintigraphy is an excellent resource for the evaluation of infection or mechanical (aseptic) loosening. Although not specific, scintigraphy is a highly sensitive modality with increased uptake in the postoperative period secondary to increased vascularity around the prosthesis as well as in the aforementioned pathological states. Bone scans are studies typically employed over the course of 3 hours, following injection of a radiotracer, typically technetium-99m.27 Aseptic loosening is more suggested on isolated, delayed increased radiotracer uptake at focal areas, such as at a stem tip (Fig. 37.8). Infection is more commonly suggested with increased uptake on all three phases of the study and a diffuse uptake about the entire prosthesis. However, low-grade infection, which not infrequently occurs in shoulder arthroplasty with such organisms as Propionobacter acnes, may be very difficult to distinguish from aseptic loosening with three-phase bone scan.

11

FIGURE 37.7 Ultrasound of the shoulder in a transverse orientation demonstrating subscapularis tear (arrow) and internal, punctate foci of polyethylene wear (block arrow). M indicates areas of metal reverberation typically seen with ultrasound of prostheses.

Leukocyte Imaging (Indium Scan) Given the often nonspecific, or confusing picture of a technetium bone scan, other radioisotopes have also gained favor. Specifically, labeled leukocyte imaging (indium-111) in concert with bone marrow imaging (technetium-99-sulfur colloid) has shown increased accuracy of greater than 95%.15 However, multiple limitations exist regarding the use of this technique including cost, direct contact with blood products, and technologists skilled in the handling of these radioisotopes. In addition, the need for extraction of 60 mL of blood, the need to image on multiple days, combined with a certain level of patient intolerance, makes this modality somewhat patient unfriendly. At our institution, given that 12

multiple other modalities are also available to assess whether a prosthesis is infected, leukocyte/marrow imaging is not typically utilized. At other institutions or facilities without expertise in MRI or aspiration, this does represent a pragmatic adjunct.

Positron Emission Tomography As it has gained popularity over the last decade, positron emission tomography (PET) studies have increased. PET studies are based on the utilization of fluorine-18-labeled glucose, which is detected on a dedicated PET scanner at sites of increased metabolic activity. Increased metabolic activity is seen in both aseptic loosening and infection and as such PET does not accurately differentiate these two entities.15 The accuracy of PET in diagnosing infection has been found to be 69% to 78%, markedly lower than that of the leukocyte/marrow imaging.15 As the cost of PET is still high and it is nonspecific in this situation, it is currently not recommended.14 P.348

13

FIGURE 37.8 A (Anterior) and B (posterior): spot delayed images from a bone scan demonstrate focal increased uptake about the glenoid, particularly inferiorly (arrows). C: Corresponding Grashey view demonstrates a prominent lucency seen about the inferior screw (arrow), indicating a loose glenoid component.

Computed Axial Tomography CT has become almost omnipresent in the world of orthopaedic imaging, particularly in the postoperative patient. A basic understanding of the modifications that are done to optimally image the postoperative patient is important as it allows the orthopaedic surgeon to realize the limitations of

14

the imaging as well as work together with the radiologist to optimize the benefits of the study. Metal will attenuate the Xray beam, resulting in a so-called hardening of the beam and generate a streak-like or scattering artifact (Fig. 37.9). The type of metal and geometry of the metal play significantly into the degree of artifact. Cobalt chrome and stainless steel produce the greatest degree of artifact while titanium and titanium alloys produce a much decreased level of artifact. As many humeral implants utilize a cobalt chrome head, the utility of this modality has been somewhat debated. Additionally, the plane with the greatest cross-sectional area of metal produces the greatest level of streaking artifact.6 Hence, in the setting of a shoulder arthroplasty, one can expect the greatest degree of artifact in the axial plane and a decreased amount of artifact in the sagittal and coronal planes or reformations (Fig. 37.4). The acquisition of the reformats is truly at the crux of ensuring diagnostic imaging. When CT scans are performed in orthopaedic imaging, typically a detail or coarse algorithm is employed to obtain the greatest degree of contrast. However, in the setting of arthroplasty, this generates a much greater amount of streak artifact. A softer algorithm, as typically utilized with abdominal imaging, is of much greater use. P.349

Although the overall resolution minimally decreases, it is truly not a diagnostic problem and the smoothness of the filter allows for adequate evaluation of the adjacent bone to evaluate for osteolysis and loosening (Figs. 37.10 and 37.11).6 Additionally, the images should be obtained at 1- to 1.5-mm intervals in the axial plane with 50% overlap and then

15

reconstructed in the sagittal and coronal planes at 1 to 2 mm. Although this does bring into effect the possibility of volume averaging (decreased spatial resolution such that two structures in close approximation are superimposed instead of clearly separated), again the decrease in the streaking artifact and overall smoothness of the images allows overall increased diagnostic acumen. By no means as accurate in evaluation of soft tissue structures, CT can be utilized to evaluate for soft tissue collections and large joint effusions as well.

FIGURE 37.9 Axial CT image through the humeral component of a shoulder

16

arthroplasty demonstrates marked streaking or beam hardening artifact even in this titanium alloy prosthesis.

FIGURE 37.10 The marked decrease in the scattering artifact in the CT coronal and sagittal planes (B and C) as compared to the CT axial plane (A). This is secondary to the relative decrease in cross-sectional area of the prosthesis affected by the X-ray beams.

IMAGING SPECIFIC ARTHROPLASTY CONDITION AND COMPLICATIONS

17

The painful or failed arthroplasty can occur for a variety of reasons. These etiologies can frequently be sorted based on the type of prosthesis that is used, hemiarthroplasty, constrained or reverse type prosthesis (RSA), or unconstrained total shoulder arthroplasty (TSA). A recent report by Bohsali et al.4 found that in the constrained arthroplasty, the most common complications were in order: scapular notching, hematoma, glenoid dissociation, P.350

aseptic loosening, glenohumeral dislocation, acromial/scapular spine fracture, infection, glenoid loosening, and nerve injury. In the unconstrained TSA, the most common complications in order of frequency were component loosening, instability, periprosthetic fracture, rotator cuff tears, neural injury, infection, and deltoid muscle dysfunction. In the hemiarthroplasty, the most common complications are glenoid erosion and progressive glenoid arthrosis, superior migration, infection, and humeral loosening.28

18

FIGURE 37.11 CT of a coronal reformat showing large areas of almost circumscribed lucency about the glenoid component indicating severe osteolysis (arrows).

19

FIGURE 37.12 Grashey views demonstrating from (A) to (B) note the increased lucency around the superior portion of the glenoid component with distraction of the component from the underlying bone.

Implant Loosening Glenoid component loosening is a frequently discussed cause of shoulder arthroplasty failure.3 , 30 Definitions of loosening include a progressive lucency over time of greater than 2 mm and, if the glenoid is divided into five components, greater than 2 mm of lucency in two or more consecutive zones.16 Sequential radiographs when compared over time can often show progression of radiolucency and other evidence of frank loosening (Fig. 37.12). Osteolysis refers to the inflammatory-mediated response against the “inert” substances of an arthroplasty, particularly the polyethylene. Osteolysis on MRI demonstrates areas of intermediate signal, close to muscle, with a well-defined area

20

of low signal.21 MRI can often demonstrate areas of subtle osteolysis before radiographic findings become apparent (Figs. 37.13, 37.14, 37.15 and 37.16). Larger areas of osteolysis, surrounding a component, are thought to equate with frank loosening of the glenoid, if other joints can be used as a source of comparison.18

FIGURE 37.13 Axial MRI images of a TSA (A cranial to B) demonstrate the normal fatty, high-signal intensity (arrows) about the anterior aspect of the glenoid component and the typical intermediate, grey signal intensity of osteolysis (block arrows) about the more posterior aspect of the glenoid component.

21

FIGURE 37.14 Arthrogram of a patient demonstrating contrast insinuating at the prosthetic bone interface consistent with the areas of osteolysis delineated on MRI (single and block arrows).

Osteolysis is typically manifest on MRI as intermediate signal of bone with surrounding low-signal intensity. This is in contradistinction to the normal high-signal fatty marrow that one expects in the appendicular skeleton of the adult patient. As a precursor to frank osteolysis, frequently seen on MRI and on ultrasound is a synovitis within the pseudocapsule, often demonstrating large areas of synovial proliferation or debris. This likely represents an intracapsular burden of particle disease before frank osteolysis can be identified. On ultrasound, punctuate foci may be seen within a joint effusion. On ultrasound, it is difficult to ascertain frank osteolysis as the metal reverberation limits evaluation of the deep structures.

22

Loosening of the humeral component is a much less frequent occurrence. The humerus can be divided into eight zones by using a modification of the Gruen classification of the hip. Zones 1 to 7 extend from lateral to medial on the AP view with the subchondral surface being referred to as zone 8.8 Sperling et al. defined those humeral components at risk for loosening as demonstrating subsidence, tilt, or P.351

2-mm lucent lines around the implant. Although more frequently seen in TSA than hemiarthroplasty, loosening of the humeral component does occur in both situations.28 Radiographs are able to show extensive changes but MRI can show subtle and extensive changes (Figs. 37.17 and 37.18).

23

FIGURE 37.15 Grashey view of the same patient in Figure 37.14 demonstrating normal TSA on radiograph.

Post Operative Infection One of the more dreaded complications of shoulder arthroplasty is infection. Much has been written in the literature about the role of hematological evaluations such as erythrocyte sedimentation rate (ESR) and C reactive protein (CRP), but these are nonspecific. If clinical suspicion is such, the referring clinician often will refer for adjunct imaging, typically MRI or nuclear medicine as these modalities are sensitive. Radiographs are frequently negative given the

24

overall lower sensitivity. When present, the findings on radiographs are similar to infection of other arthroplasties. A focal destructive process, rapidly progressing irregular radiolucency, aggressive periostitis, and soft tissue mass/emphysema may be present (Fig. 37.19). At our institution,

99m

Tc-methylene diphosphonate bone scans are

sometimes utilized to asses for infection. As stated previously, although there is an increased accuracy of P.352

leukocyte/marrow imaging for assessment of infection, there are drawbacks to this modality including expense, labeling of blood products, and difficulty for the referring patients (studies require multiple, lengthy imaging times and are difficult for the debilitated patient). Infection typically presents with increased flow, pool, and delayed uptake. The classic pattern is to have diffuse uptake although this is not always manifest (Fig. 37.20). Another frequent finding in the setting of infection is focal soft tissue uptake.23 On MRI, infection can be virtually diagnostic on occasion and at other times merely suggested. The classic findings are very high-signal intensity (approaching fluid) in the soft tissue, diffuse areas of marrow edema, a lamellated periosteal reaction, and large, localized adenopathy21 (Fig. 37.21).

25

FIGURE 37.16 Axial MRI image demonstrating osteolysis (arrow) about the anterior glenoid component, almost a fluid signal about the posterior component and a loss of glenoid component apposition to the native bone (block arrow) indicating loosening. NM, Normal marrow for comparison.

26

FIGURE 37.17 Normal radiograph in (A). B (Coronal) and (C) (Sagittal): MR images demonstrate focal areas of osteolysis along the humeral shaft (arrow).

27

FIGURE 37.18 Osteolysis on radiographs (arrows in A) as well as on MRI (arrows in B, C). Grashey view of subsequent revision (D).

28

FIGURE 37.19 Grashey views: When comparing (A) to (B) (2-year time interval), notice the interval destructive process (arrows) of the proximal, lateral humeral cortex in this patient with an infected reverse prosthesis.

Although imaging is of use, it rarely obviates the need for aspiration in the setting of clinical infection. However, given negative findings, particularly on MRI and nuclear medicine, infection is very unlikely, particularly given the high sensitivity of these modalities.2

Implant Instability The shoulder, as an unconstrained joint, is inherently unstable. Because the glenohumeral stability postoperatively in an unconstrained prosthesis is dependent upon the adequacy of the soft tissue (capsule and rotator cuff), the health of those tissues play an important role in postoperative implant stability. Conditions in which these are deficient (rotator cuff tear, capsular stretch, or laxity) may be

29

associated with postoperative instability of an unconstrained implant. An even greater problem may be when a more constrained implant such as a reverse shoulder arthroplasty becomes unstable. It is unclear which of the many factors potentially leading to instability of a reverse prosthesis dominates, but these may include poor soft tissue, a large dead space, lack of adequate tension in the articulation, superior position of the metaglene contribution in adduction, poor deltoid tension, or combinations of the above. Instability of a shoulder arthroplasty is usually described based on the direction of the instability. The two most common P.353

are anterior and superior. Although posterior and inferior instabilities do occur, they are much more infrequent as seen in the work by Neer et al.20 Anterior instability can be caused by multiple factors including subscapularis insufficiency, anterior glenoid erosion, excessive humeral anteversion, and anterior deltoid dysfunction.12 As described by Wirth and Rockwood, it is not believed that anterior instability will result from component malposition or anterior deltoid dysfunction. Subscapularis is implicated as the most important component in progressing to anterior instability. The subscapularis may become disrupted from poor surgical technique (as it is taken down during shoulder arthroplasty and then reattached to the lesser tuberosity), overstuffing of the glenohumeral joint, or poor tissue/progressive degeneration of the subscapularis.36 The subscapularis disruption can be particularly well seen on MRI or on ultrasound. MRI and ultrasound demonstrate the

30

subscapularis best on the axial sequences or an axial equivalent (Fig. 37.22).

FIGURE 37.20 A: (Flow and pool images) demonstrates mildly increased flow with marked increased pooling (arrow). B: (3-hour delay study) demonstrates diffuse and increased delayed uptake (arrows). Subsequent aspiration confirmed diagnosis of infection.

Superior instability is related to rotator cuff insufficiency, coracoacromial arch defect, and less than ideal implant position. The crux of the problem with superior migration is that it causes a force-couple imbalance between the rotator cuff and the deltoid causing eccentric wear of the glenoid component in the setting of a total arthroplasty or may cause substantial pain with a destabilized center of rotation in the setting of a hemiarthroplasty.4 , 31 Radiographs frequently are able to demonstrate a loss of the acromiohumeral interval (typically at least 6 mm) or interval progression in a narrowing of the acromiohumeral interval over time (Fig. 37.23).

31

Ultrasound has been documented to be excellent at evaluating supraspinatus tears in the setting of shoulder arthroplasty, particularly on the coronally oriented images.25 MRI, as described previously, when performed using the modifications of imaging parameters, can also demonstrate the supraspinatus and infraspinatus particularly well on the oblique coronal images (Figs. 37.19 and 37.20). Another advantage of MRI is the ability to delineate severe muscle atrophy and incompetent musculature, despite an intact tendon. This condition is know to precipitate superior instability as well12 (Figs. 37.24 and 37.25). Superior instability in the setting of a shoulder arthroplasty may be treated with the reverse shoulder arthroplasty.17

FIGURE 37.21 A (Coronal inversion recovery) and B (Coronal Proton Density) images demonstrate a mildly, heterogeneous fluid collection with a surrounding amount of edema extending into the soft tissue (E) and multiple, enlarged, nonfatfilled axillary nodes (N) in this patient with an infected prosthesis.

32

FIGURE 37.22 Axial MRI demonstrates disrupted subscapularis (arrow) adhered to the anterior joint capsule with profound atrophy of the muscle belly.

P.354

33

FIGURE 37.23 Grashey views: From (A) to (B) (approximately 1-year time interval), note the superior riding of the humeral head in this now cuff-deficient patient status posthemiarthroplasty.

The reverse prosthesis has been associated with a number of complications and its exact role, while clearly useful in the overall armamentarium of implant surgery, is still being clarified by clinicians.4 The most common complication of the reverse prosthesis is notching at the inferior scapula, thought due to attrition from the abutment of the inferior glenoid to the humeral component.24 However, the clinical relevance of notching is still debated.34 When the reverse prosthesis is implanted, it is crucial that the metaglene is flush with the native glenoid for long-term success.10 Additionally, it has been found that outside of the complications of unconstrained arthroplasty (particularly glenoid loosening in this prosthesis), the reverse prosthesis has the proclivity for dislocation,

34

dislodgement of the metaglene or baseplate, and acromial fracture.5

Glenoid Erosion and Arthrosis Another clear advantage to MRI is the evaluation of cartilage utilizing proton density, high-resolution imaging. Shoulder hemiarthroplasty has long been known to be complicated by glenoid erosion and progressive glenoid arthrosis. While there may indeed be evidence of glenoid wear on plain radiographs (sclerosis, cysts, abutment of the humeral head implant on glenoid bone, and progressive narrowing of the joint space), MRI may prove helpful at an earlier stage. MRI, by allowing evaluation of the cartilage, provides information about cartilage loss prior to extensive bony loss9 (Fig. 37.6).

35

FIGURE 37.24 A (Coronal MRI) demonstrates discontinuity of a markedly degenerated supraspinatus tendon (arrow). B (Panoramic, coronal ultrasound) demonstrates a high riding humeral component with the glenoid (G) component inferior causing a reverberation artifact. There is a debris/fluid-filled gap in the expected location of the supraspinatus (arrow) with the tendon being disrupted.

36

FIGURE 37.25 Coronal MRI (A anterior to B): Disrupted Supraspinatus (arrow in A) and infraspinatus (arrow in B) with severe fatty infiltration of the musculature (F).

Other complications and potential sources of pain and implant failure include heterotopic ossification, deltoid muscle dysfunction, neural injury, periprosthetic fracture, and tuberosity malunion or nonunion. P.355

CONCLUSION In the setting of a painful arthroplasty, the treating orthopaedic surgeon should be armed with information relating to the modification and use of multiple imaging modalities to begin to narrow down the multiple potential causes of the shoulder pain. A careful history and physical examination, followed by plain radiographs and more

37

sophisticated imaging techniques, may provide important information as to whether revision surgery may be warranted. The difficulty of evaluating and treating the painful arthroplasty underscores the necessity of careful preoperative evaluation, attention to surgical detail, and the importance of postoperative rehabilitation associated with the initial arthroplasty.

References 1. Aliabadi P, Weissman B, Thornhill T: Evaluation of a nonconstrained total shoulder prosthesis. Am J Roentgenol 151(6):1169-1172, 1988. 2. Al sheikh W, et al: A prospective comparative study of the sensitivity and specificity on in 111 leukocyte, gallium 67, bone scintigraphy, and roentgenograms in the diagnosis of osteomyelitis with and with out orthopedic prosthesis. J Nucl Med 23:29-30, 1982. 3. Anglin C, Wyss U, Pichora D: Mechanical testing of shoulder prostheses and recommendations for glenoid design. J Shoulder Elbow Surg 9:323-331, 2000. 4. Bohsali K, Wirth M, Rockwood C: Current concepts review: Complications of total shoulder arthroplasty. J Bone Joint Surg Am 88:2279-2292, 2006. 5. Boileau P, et al: The grammont reverse shoulder prosthesis: Results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15(5):527540, 2006. 6. Buckwalter KA, Parr JA, Choplin RH, Capello WN: Multichannel CT imaging of orthopedic hardware and implants. Semin Muscoskel Radiol 10(1):86-97, 2006.

38

7. Frazzini VI, Kagetsu NJ, Johnson CE, Destian S: Internally stabilized spine: Optimal choice of frequency-encoding gradient direction during MR imaging minimizes susceptibility artifact from titanium vertebral body screws. Radiology 204:268-272, 1997. 8. Gruen T, Mcniece G, Amstutz H: Modes of failure of cemented stem-type femoral components. A radiographic analysis of loosening. Clin Orthop Relat Res 141:17-27, 1979. 9. Haines JF, Trail IA, Nuttall D, Birch A, Barrow A, et al: The results of arthroplasty in osteoarthritis of the shoulder. J Bone Joint Surg Br 88-B:496-501, 2006. 10. Harman M, Frankle M, Vasey M, Banks S: Initial glenoid component fixation in “reverse” total shoulder arthroplasty: A biomechanical evaluation. J Bone Joint Surg Am 14(1 Suppl S):162S-167S, 2005. 11. Hayes R, Flatow E: Total shoulder arthroplasty in the young patient. AAOS Instr Lect 50:73-87, 2001. 12. Hennigan S, Iannotti J: Instability after prosthetic arthroplasty of the shoulder. Orthop Clin N Am 32(4):649-659, 2001. 13. Kozak L, Owings M, Hall M: National hospital discharge survey: 2002 annual summary with detailed diagnosis and procedure data. Vital Health Stat 13 158:1-199, 2005. 14. Love C, Marwin SE, Tomas MB, et al: Diagnosing infection in the failed joint replacement: A comparison of coincidence detection

18

F-FDG and

111

In-labeled

leukocyte/ 9 9 m Tc sulfur colloid marrow imaging. J Nucl Med 45(11):1864-1871, 2004. 15. Love C, Tomas MB, Marwin SE, et al: Role of nuclear medicine in diagnosis of the infected joint replacement. RadioGraphics 21:1229-1238, 2001.

39

16. Martin S, Zurakowski D, Thornhill T: Uncemented glenoid component in total shoulder arthroplasty. J Bone Joint Surg Am 87:1284-1292, 2005. 17. McFarland EG, Sanguanjit P, Tasaki A, et al: The reverse shoulder prosthesis: A review of imaging features and complications. Skeletal Radiol 35:488-496, 2006. 18. Naraghi A, White L: Magnetic resonance imaging of joint replacements. Semin Muscoskel Radiol 10(1):98-106, 2006. 19. Neer CI: Articular replacement of the humeral head. J Bone Joint Surg Am 37:215-228, 1955. 20. Neer C, Watson K, Stanton F: Recent experience in total shoulder replacement. J Bone Joint Surg Am 64:319-337, 1982. 21. Potter HG, Nestor BJ, Sofka PM: Magnetic resonance imaging after total hip arthroplasty: Evaluation of periprosthetic soft tissue. J Bone Joint Surg Am 86A(9):1947-1954, 2004. 22. Rosenthal S, Jones P, Wetzel L: Phase inversion tissue harmonic sonographic imaging. Am J Roentgenol 176:13931398, 2001. 23. Schneider R: Radionuclide techniques, in diagnosis of bone and joint disorders. 388-391, 2002. 24. Sirveaux F, Favard L, Oudet D: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. J Bone Joint Surg Am 86:388-395, 2004. 25. Sofka C, Adler R: Original report. Sonographic evaluation of shoulder arthroplasty. Am J Roentgenol 180(4):1117-1120, 2003. 26. Sofka C, Potter H: MR imaging of joint arthroplasty. Semin Muscoskel Radiol 6(1):79-85, 2002.

40

27. Spangehl MJ, Younger AS, Masri BA, Duncan CP: Diagnosis of infection following total hip arthroplasty. Instr Course Lect 47:285-295, 1998. 28. Sperling J, Cofield R, Rowland C: Minimum fifteen-year follow-up of Neer hemiarthroplasty and total shoulder arthroplasty in patients aged fifty years or younger. J Shoulder Elbow Surg 13(6):604-613, 2004. 29. Sperling JW, Potter HG, Craig EV, et al: Magnetic resonance imaging of the painful shoulder arthroplasty. J Shoulder Elbow Surg 11(4):315-321, 2002. 30. Stone K, Grabowski J, Cofield R: Stress analyses of glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 8:151-158, 1999. 31. Visotsky JL, Basamania C, Seebauer L, et al: Cuff tear arthropathy: Pathogenesis, classification, and algorithm for treatment. J Bone Joint Surg Am 86:35-40, 2004. 32. Walde TA, Weiland DE, Leung SB, et al: Comparison of CT, MRI, and radiographs in assessing pelvic osteolysis: A cadaveric study. Clin Orthop Relat Res 437:138-144, 2005. 33. Wendt RE 3rd, Wilcott RE 3rd, Nitz W, et al: MR imaging of susceptibilityinduced magnetic field inhomogeneities. Radiology 168:837-841, 1988. 34. Werner CM, Steinman RA, Gilbert M, Gerber C: Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the delta III reverse ball-and-socket prosthesis. J Bone Joint Surg Am 87:1476-1486, 2005. 35. White L, Kim J, Mehta M: Complications of total hip arthroplasty: MR imaging-initial experience. Radiology 215:254-262, 2000.

41

36. Wirth M, Rockwood C: Complications of total shoulder replacement arthroplasty. J Bone Joint Surg Am 78:603-616, 1996.

42

Chapter 38 Revision Shoulder Arthroplasty Mark E. Morrey John W. Sperling Robert H. Cofield Prosthetic arthroplasty of the shoulder began in the United States about 50 years ago with humeral head replacements. The contemporary style of total shoulder arthroplasty (TSA) has been used for almost 25 years. Early experience with TSA included constrained designs that have all but been abandoned. Therefore, the large majority of patient experience is with unconstrained shoulder arthroplasty, such as designed by Neer or similar variations. As one would expect, most patients with unconstrained TSA, as those with hip and knee arthroplasty, generally do quite well. However, over time, the need for revision surgery has increased so that now on a percentage basis it is not much different than revisions performed in other major joints (8% in one large review).45 The scientific literature is beginning to reflect the slowly increasing demand for revision TSA. A literature search conducted from the years 2000 to 2009 revealed over 100 articles on revision surgery. These articles dealt with risk factors for revision, instability, wear patterns, bone grafting, infection, rotator cuff (RC) tear, aseptic loosening, augmented glenoids, conversion procedures, polyethylene exchange, reverse arthroplasty, and surgical technique as well as general outcomes, to name a few.1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 18 , 20 , 21 , 22 , 24 , 25 , 26 , 27 , 2 8 , 29 , 30 , 31 , 32 , 33 , 34 , 36 , 37 , 38 , 39 , 41 , 43 , 44 , 46 Much of the discussion on several of these techniques is dealt with in

1

other chapters. Nevertheless, as these operations become more frequent, attention must be paid to problems encountered, techniques for revision, and the outcomes of revision shoulder arthroplasty. To effectively treat the patient who requires revision shoulder arthroplasty, the surgeon must have information in seven areas: (a) the pathoanatomy of the disease which led to the original shoulder arthroplasty; (b) information about the original operative procedure and postoperative care; (c) knowledge of the current situation in the shoulder; (d) the patients' needs, cooperative capacity, and general health; (e) treatment options to solve the problem; (f) technical details of the operative procedure; and (g) the benefits and limitations of the procedure. TABLE 38.1 REOPERATIONS ON HUMERAL HEAD REPLACEMENTS

Complications

Treatment

Glenoid arthritis

Glenoid component

19

Revision of humeral head replacement

2

Revision to total shoulder arthroplasty

2

Soft tissue repair

1

Tendon repair

2

Instability

Rotator cuff tear

No.

2

Impingement

Acromioplasty

1

Tuberosity repair

1

Infection

Component removal

1

Nerve injury

Muscle transfer

1

Fractured acromion

Open reduction and internal fixation

1

Not stated

2

Total 33 (5.7%)

Addressing the last six of the above-mentioned areas will include presenting information from TSA series outlining the problems identified and their frequency, reviewing our experience with revision surgery, and presenting information from the literature that directly addresses various aspects of revision surgery. Finally, recommendations for diagnostic evaluation, treatment planning, surgical indications, specific technical options, complications, and the limitations of revision shoulder surgery will be discussed.

REOPERATIONS ON SHOULDER ARTHROPLASTIES (LITERATURE REVIEW) 3

To collect information about the frequency of reoperations on shoulder arthroplasties, the specific complications encountered, and the treatments used, we reviewed 63 reported patient series. Thirty-four of these series with 581 operated shoulders related information on humeral head replacement. Information about these shoulders is displayed in Table 38.1. The majority of revisions were for glenoid arthritis associated with pain, and treatment usually included placing a glenoid component. All other complications were quite infrequent. Similarly, there were nine reported series with 307 operated shoulders on reoperations following constrained total shoulder replacements (Table 38.2). The problems leading P.357

to reoperation were much more varied than those seen with humeral head replacement alone and were also much more frequent. As this type of total shoulder replacement is no longer used and so few patients are currently seen needing revision of this type of shoulder arthroplasty, additional information about this type of implant and revision techniques will not be presented. TABLE 38.2 REOPERATIONS ON CONSTRAINED TOTAL SHOULDER REPLACEMENTS

4

Complication

Treatment

Glenoid loosening

Revision

11

Removal

5

Revision

10

Removal

2

Prosthesis bent/fractured

Revision

9

Infection

Removal

5

Fracture

Revision

2

Removal

1

Internal fixation

1

Humeral loosening

Revision

2

Humeral and glenoid loosening

Revision

1

Dehiscence

Closure

1

Instability

No.

5

Ankylosis

Clearance

1

Allergy to components

Removal

1

Total 52 (16.9%)

There were six reported patient series with 145 operated shoulders presenting information on reoperations on unconstrained total shoulder replacements that had enough difference in their design parameters from the Neer type of implants that it is useful to present separate information about them (Table 38.3). Revision surgery was done on 12 shoulders for four well-defined reasons. Finally, 14 reported series with 841 operated shoulders were studied defining the reoperations on Neer or Neer-like unconstrained total shoulder replacements. Of the 841 reported shoulders, 26 needed revision for eight different problems with the three most common complications leading to revision surgery being glenoid loosening, RC tearing, or periprosthetic humeral fracture (Table 38.4). With the emergence of the reverse prosthesis in the 1990s, the literature has begun to shed light on outcomes and the emergence of problems requiring revision. In 2007, Wall et

6

al.48 reviewed 186 patients with 191 retained reverse TSA prostheses followed for an average of just over 3 years. While patient satisfaction and Constant scores used as primary outcome measures improved, dislocation in 15 cases and infection in 8 were among the most common complications among the 199 shoulders that were followed for 2 years or were revised prior to the minimum 2-year follow-up. The SOFCOT multicenter study revealed a 4.1% (22 of 527 cases) rate of aseptic loosening of the glenoid component with average follow-up of 52 months in patients with cuff tear arthropathy.47 Finally, despite encouraging short-term results, review of the literature reveals complications, in order of frequency, to be scapular notching, glenoid dissociation with baseplate failure, aseptic loosening, glenohumeral dislocation, fracture of the glenoid or acromion, infection, and loosening of the humeral component. Concomitant revision surgery rates match these problems and range from 4% to 33% in various studies.17 , 40 , 49 All shoulders were revised to either a hemiarthroplasty or a reverse prosthesis. Nevertheless, Sirveax's Kaplan Meier projected survivorship of 29.8% at 8 years is especially disappointing and underscores the need for strict patient selection with this type of implant. TABLE 38.3 REOPERATIONS ON UNCONSTRAINED TOTAL SHOULDER REPLACEMENTS OTHER THAN NEER

7

Complication

Treatment

Instability

Revision

4

Glenoid loosening

Remove component

2

Component revision

1

Removal

2

Revision

1

Tendon repair

2

Infection

Rotator cuff tear

No.

Total 12 (8.3%)

TABLE 38.4 REOPERATIONS ON NEER, UNCONSTRAINED TOTAL SHOULDER REPLACEMENTS

8

Complications

Treatment

No.

Glenoid loosening

Component revision

6

Remove component

5

Rotator cuff tear

Tendon repair

5

Fracture

Internal fixation

3

Component revision

1

Impingement

Acromioplasty

2

Acromioclavicular arthritis

Distal clavicle excision

1

Infection

Remove components

1

Instability

Arthrodesis

1

Nerve injury

Muscle transfer

1

Total 26 (3.1%)

9

ETIOLOGY OF ARTHROPLASTY FAILURE (MAYO CLINIC EXPERIENCE) As the frequency of revision surgery has begun to steadily increase in the literature, so has there been a need for revision shoulder surgery in our own practice, including patients who had their initial surgery at our institution and those who were referred for revision surgery. Tables 38.1 and 38.3 outline the etiologies of failure of humeral head replacement and TSA seen in patients treated with revision surgery at our institution. Table 38.5 outlines failures of humeral head replacement from those referred from outside facilities and revised at our institution. As is reflected in the literature, the major reason for revision of humeral head replacement was painful glenoid arthritis, although in these patients, we also encountered a substantial number of RC or tuberosity problems and glenohumeral instability. Of those 87 shoulders referred from outside facilities with failure of a humeral head replacement, 34 had only one pathologic abnormality (usually glenoid arthritis), 38 had two pathologic abnormalities, 13 had three pathologic abnormalities, and 2 had four abnormalities P.358

needing treatment. There was a strong association between humeral malposition and instability with glenoid arthritis in these patients. Nevertheless, revision surgery for failure of humeral head replacement was not unduly complex (Fig. 38.1). TABLE 38.5 REOPERATIONS ON 87 HUMERAL HEAD REPLACEMENTS REFERRED FROM OUTSIDE HOSPITALS

10

Complication

Percent

Glenoid arthritis

75.0%

Instability

17.2%

RC tear

33.3%

Loosening

19.5%

Malpositioning

25.3%

Fracture

6.9%

Infection

1.1%

Number of problems identified in 87 humeral head replacements

One problem

34.0%

Two problems

38.0%

Three problems

13.0%

Four problems

2.0%

11

FIGURE 38.1 A, B: Example of glenoid arthritis with posterior subluxation following hemiarthroplasty. C,D: The patient underwent revision to TSA with the use of an ingrowth glenoid component. TABLE 38.6 FAILURE OF TOTAL SHOULDER REPLACEMENT (NO. = 117)

12

Etiologies

No.

Instability

73

Rotator cuff tear

54

Glenoid loosening

36

Component material failure

28

Humeral loosening

23

Component malposition

10

Infection

3

Fracture

1

Failure of TSA is somewhat different. The etiologies for failure in 117 shoulders requiring revision are outlined in Table 38.6. One can easily recognize that many factors are involved with failure of TSA and can appreciate that multiple factors might well be present in a single shoulder. In defining this further, we found that 37 shoulders only had one pathologic abnormality needing correction while 53 had two, 24 had three, and 3 had four types of etiologic pathologic abnormalities needing correction. For example, for those shoulders referred from outside facilities, 27% had a RC tear

13

and 24% posterior instability. As such, it is rather straightforward P.359

to recognize the implications. The current shoulder situation requires careful analysis, and detailed preoperative planning is necessary so that all potential etiologies of failure can be addressed.

PATIENT SERIES ON REVISION PROCEDURES In 1982, Neer and Kirby reported on revision of humeral head and total shoulder arthroplasties.8 In their article, they presented a detailed evaluation methodology, including preoperative considerations, surgical considerations, and postoperative considerations. More than one factor causing failure was present in almost every case. Predominant causes of failure in their patients included deltoid scarring and detachment, tightness of the subscapularis and anterior shoulder capsule, adhesions in the subacromial bursa and impingement of the RC, prominence of the greater tuberosity or retraction of the tuberosity, loss of humeral bone length, and eccentric glenoid wear or central wear of the glenoid. Finally, the lack of a supervised rehabilitation program contributed to failure in almost all of the arthroplasties undergoing revision surgery. Thirty-four of the shoulders so evaluated were revised to a TSA of the unconstrained type. A full rehabilitation program and return to near-normal function were obtained in 10 patients, but, overall, the results were not as good as other diagnostic categories for patients undergoing TSA. Usually, satisfactory pain relief was

14

achieved, and function for many of the activities of daily living was obtained. Revision was considered a most technically difficult procedure due to a combination of bone loss, scarring, muscle weakness, and infection. Caldwell and coauthors3 reported on 18 shoulders requiring revision of prosthetic components, including 10 with previous humeral head replacement and 8 with previous TSA. Nine of the humeral head replacements were revised to total shoulder replacements because of glenoid arthropathy. Revision for total shoulder replacements included revision of the glenoid components for loosening or for glenoid malposition in three, removal of a loosened glenoid component in two, and revision for instability in three. Thirteen of the revision arthroplasties were available for follow-up at a minimum of 2 years. Preoperative HSS shoulder score was 38 with the postoperative score being 70. Five shoulders required further revision surgery. These authors concluded that the outcome of revision arthroplasty did not approach the results of primary arthroplasty, and some patients will need to be rehabilitated with limited goals because of soft tissue or bony defects. Wirth and Rockwood reviewed data concerning 38 failed, unconstrained shoulder arthroplasties.12 They also recognized that failure was often multifactorial. The most common complication in their patients leading to revision was symptomatic glenohumeral instability. Other causes of failure included detachment of the anterior deltoid, glenoid component loosening, glenoid bone erosion following hemiarthroplasty, humeral component loosening, greater tuberosity malunion or retraction, fibrous or osseous

15

ankylosis, infection, and dissociation of a modular humeral component. Moeckel identified 10 of 236 shoulders having replacement arthroplasty that developed symptomatic instability of the shoulder requiring revision arthroplasty.7 The instability was anterior in seven and posterior in three. The anterior instability was due to rupture of the repaired subscapularis tendon. Operative treatment included mobilization and repair of the tendon, but three of the seven operated shoulders continued to have instability. They underwent reoperation, including anterior tissue reinforcement with a tendo-achilles allograft. This second procedure achieved stability. The posterior instability was caused by many factors, and treatment consisted of correction of any soft tissue imbalance and revision of the implants when needed. Following revision surgery for the instability, all patients lost some motion, but pain relief was achieved and the patients were much improved compared to their preoperative situation. Dines et al.13 more recently published on 78 shoulders and categorized the need for revision into two major groups: (a) those with osseous or component-related problems and (b) those with soft tissue deficiency. Group 1 consisted of four cohorts of shoulders: 22 treated with revision of the glenoid component, 16 treated with conversion of a hemiarthroplasty to a TSA because of glenoid arthrosis, 8 treated with revision of the humeral stem, and 4 treated for a periprosthetic fracture. Category 2 consisted of five cohorts of shoulders: 10 treated with RC repair following total shoulder replacement, 4 with a failed tuberosity reconstruction, 4 with cuff tear arthropathy, 5 with instability, and 5 with infection. They found that the outcome of revision total shoulder replacement

16

could be predicted on the basis of the indication for the revision procedure. Component revisions, excluding humeral head revision for salvage, provided the best results, and soft tissue reconstructions and revisions for infection could be expected to yield poorer results overall.

Revision of the Glenoid Several recent studies have examined revisions for specific issues related to the glenoid component. Fox et al.16 examined different component designs and the factors influencing the need for revision surgery. In their analysis, they identified six types of glenoid components: Neer II all-polyethylene, Neer II metal-backed, Cofield 1 metal-backed bone-ingrowth, Cofield 1 all-poly keeled, Cofield 2 all-poly keeled, and Cofield 2 all-poly pegged. They found that of the 1542 total shoulder replacements examined, revision was required in 121 shoulders for glenoid component failure. The glenoid component type was significantly associated with component revision and that survival is improved with cemented all-polyethylene glenoid components. Furthermore, revision of cemented all-polyethylene components may be lessened with the use of pegged components in their early follow-up. Similarly, Nho et al.27 examined retrieved glenoid components to analyze the mechanisms of failure and found that of the 78 glenoid components that were retrieved, scratching, pitting, and burnishing were the most common and most severe types of polyethylene wear leading to revision. Furthermore, the damage observed was most commonly focused in the inferior quadrant of the glenoid. They theorized that there was a propensity for a humeral impingement

17

leading to glenoid loosening due to the edge deformation secondary to eccentric forces of the humeral head on the glenoid rim. Antuna et al.1 reviewed the results of 48 shoulders that underwent glenoid component revision surgery at a mean follow-up of 4.9 years (range, 2-12 y). The indications for surgery were glenoid component loosening in 29 shoulders, glenoid implant failure in 14 shoulders, and glenoid component malposition or wear leading to instability in 5 shoulders. Thirty shoulders underwent implantation of a new glenoid component and 18 shoulders underwent removal of the component and bone grafting due to bone deficiencies. There was significant pain relief, improvement in active elevation, external rotation, and satisfaction with revision glenoid surgery (P < 0.05). Patients without a glenoid component were significantly less P.360

satisfied with the procedure compared to those patients who underwent reimplantation of a glenoid component (P = 0.01). Seven shoulders that underwent placement of a new glenoid component and five shoulders that underwent removal without reimplantation required revision surgery. Rodosky and Bigliani reported on surgical treatment of failed glenoid components in nonconstrained shoulder arthroplasty.9 Twenty-five patients were treated. Eighteen components failed because of loosening, six all-polyethylene components fractured at the base of the prosthetic keel, and one glenoid had severely worn polyethylene exposing the metal backing. At surgery, two of these patients were recognized to have infection. In these patients, both the

18

glenoid and humeral components were removed. The glenoid component was removed in an additional 9 patients, and the component was revised in 14 patients. At an average 5-year follow-up in 24 patients, pain relief was achieved in 19 and there was little or no improvement in pain in 5 patients. Both replacement of the glenoid component and glenoid component removal led to satisfactory results in most patients; however, the results in the replacement group were slightly better overall, both in respect to pain relief and function. Deutsch et al.12 in 2007 retrospectively reviewed 32 patients who underwent glenoid revision surgery after TSA to compare the results of revision TSA with those of revision hemiarthroplasty and to identify factors associated with poor results after revision shoulder arthroplasty for glenoid component loosening. Results were reviewed at a mean follow-up of 4 years (range, 2-8 y). They found that glenoid reimplantation resulted in significant pain relief (P < 0.0001), improvement in American Shoulder and Elbow Surgeons (ASES) score (P < 0.02), and rotation (24-44 degrees, P < 0.004). However, revision to a hemiarthroplasty also resulted in significant relief (P < 0.01) and improvement in ASES score (P < 0.05). Therefore, they concluded that for the treatment of glenoid loosening without glenohumeral instability, both reimplantation of a glenoid component and revision to a hemiarthroplasty improved function, satisfaction, and level of pain but that reimplantation of a new glenoid component offered greater improvements in pain (P < 0.008) and external rotation (increase of 20 vs. 3 degrees, P < 0.03) compared with hemiarthroplasty. Furthermore, for patients with preoperative glenohumeral instability, revision surgery did not improve motion, function, or pain significantly. The risk

19

factors they identified with a poor outcome after revision arthroplasty included persistent glenohumeral instability, RC tears, and malunion of the greater tuberosity. Cheung et al.8 in 2008 reported on the outcomes of patients who underwent revision for glenoid component loosening. They identified 68 shoulders and categorized them into two groups. Group I consisted of 33 shoulders that underwent placement of a new glenoid component, and group II consisted of 35 shoulders that had removal and bone grafting without glenoid reimplantation. They found that there was significant overall improvement in pain from preoperation to postoperation in 23 of 33 shoulders in group I and in 24 of 35 in group II. They did not, however, find a significant change in motion except for active elevation in group I. Importantly, the rate of survival free of reoperation at 5 years was 91% (95% confidence interval, 81%-100%) in group I and 78% (95% confidence interval, 63%-96%) in group II (P = 0.3019). When the Neer result rating was applied, nine shoulders in group I and three in group II had an excellent or satisfactory result (P = 0.0432). They concluded that there is a slight clinical benefit to reimplanting a glenoid component when structurally possible. Finally, Neyton et al.25 in a multicenter trial reported on the overall outcome after revision TSA as a function of therapeutic options for the treatment of loose glenoid components. Nineteen reimplantations of a cemented glenoid, 12 “glenoplasties” without reimplantation, and 5 inverted prosthesis implantations were performed in their series. They found that function scores improved in all patients despite treatment. However, bone graft reconstruction of the bone loss prior to reimplantation of the glenoid led to better results

20

than simple removal of the loosened implant and although effective in relieving pain simple removal had a modest effect on motion. The remaining amount of glenoid bone stock was the key to functional outcome after surgical repair, and they recommend cortical grafts as opposed to cancellous. Finally, inverted prostheses offered a therapeutic solution worth examining in those patients with RC tears and glenoid loosening.

Revision from Hemiarthroplasty to TSA With regard to hemiarthroplasty revision, Sperling and Cofield reviewed the results of 18 patients who underwent revision to TSA for glenoid arthritis.10 The indications for the hemiarthroplasty were trauma (10 shoulders), osteoarthrosis (four), rheumatoid arthritis (two), and osteonecrosis secondary to the use of steroids (two). The mean interval between the hemiarthroplasty and the total shoulder replacement was 4.4 years (range, 0.8-12.7 y). The mean score for pain in the shoulder decreased from 4.3 points before the revision to 2.2 points after revision (P = 0.0001). The mean active abduction increased from 94 degrees before the revision to 124 degrees after revision (P = 0.01), and the mean external rotation increased from 32 to 58 degrees (P = 0.007). Two shoulders needed another operation after the revision because of a late infection in one and particulate synovitis associated with instability in the other. Carroll et al.4 in 2004 added a series of 16 patients converted from hemiarthroplasty to TSA for pain. The mean interval from the time of hemiarthroplasty to revision TSA was 3.5 years (range, 11 mo to 10.5 y). At a mean 5.5-year follow-up (range, 2-14 mo), the results were excellent in 3 of 15 (20%),

21

satisfactory in 5 of 15 (33%), and unsatisfactory in 7 of 15 (47%). The mean ASESs score was 73.6 (range, 46.7-95) out of a possible 100. The mean visual analog pain score was 2.4 (range, 0-6) out of 10. Evidence of posterior glenoid erosion was found in 64% (7/11) of these patients. On the basis of the complexity of the surgery and the 47% unsatisfactory rate, they concluded that revision of a failed hemiarthroplasty to a TSA is a salvage procedure whose results were inferior to those of primary TSA. Hattrup et al.20 examined 17 patients revised to TSA for pain. Their mean time interval to revision was 36.4 (range, 6-144) months. There were seven (41.2%) excellent, five (29.4%) satisfactory, and five (29.4%) unsatisfactory results. Visual analog pain scores decreased from 8.8 to 2.4, flexion improved from 73 to 124 degrees, abduction from 63 to 115.6 degrees, and external rotation from 12.1 to 46.8 degrees. In the 13 shoulders with sufficient data, the ASESs score was 76.8, and the Simple Shoulder Test score was 9.5. Humeral stem revision was necessary for poor stem position or improved exposure in 12 shoulders. They concluded that conversion of humeral head replacement to TSA may have excellent results, but the surgery is difficult, and unsatisfactory results were frequent.

Revision for Fracture There have been reports concerning humeral fractures after shoulder arthroplasty. Wright and Cofield50 identified nine such fractures following 499 shoulder arthroplasties. P.361

The arthroplasties were performed either for rheumatoid

22

arthritis or for the sequelae of trauma. Six fractures were centered at the tip of the prosthesis with one fracture extending proximally. Three other fractures involved the humeral shaft distal to the implant and extended into the distal humeral metaphysis. Two fractures that had unacceptable initial alignment were treated successfully with acute operative intervention. Four other fractures healed with nonoperative treatment. Three others treated with initial nonoperative treatment failed to heal; two eventually united after revision of the prosthesis and bone grafting was performed. Boyd reported that humeral fracture after arthroplasty failed to heal with nonoperative methods in five of seven patients.2 All five ultimately healed after operative treatment. Among the patients in that series, mobility became more restricted compared to the preinjury status in five of the six patients in whom the fracture healed. In the series by Wright, six of the eight patients in whom the fracture united had approximately the same range of motion of the shoulder as before the fracture. Kumar et al.23 reviewed 19 of 3091 with periprosthetic fracture after TSA to determine the results of treatment, risk factors, and the rates of reoperation. Of the 19 patients with fracture, 16 patients were acceptable for review. The average time from the arthroplasty to the fracture was 49 months, and seven of the patients had severe osteopenia. Although all 16 fractures healed, they found that fracture locations were important to the overall treatment plan. They felt that for fractures occurring at the tip of the prosthesis with no extension proximally or distally (a type B fracture by their classification), if union had not been achieved by 3 months,

23

surgery should be performed. Furthermore, if fractures were associated with loose implants, revision to a long stemmed implant should be entertained. Similarly, Krakauer and Cofield recommended a trial of closed treatment, if satisfactory reduction could be obtained and maintained, but, if acceptable alignment could not be achieved or a delayed or nonunion develops, surgery should be undertaken.6 This would include internal fixation with a plate, screws, and cerclage if the prosthesis is well fixed or revision with a long-stemmed prosthesis if the prosthesis is loose. Autogenous bone grafting should be used in conjunction with surgical intervention.

Revision for Aseptic Loosening Cil et al. reported on 38 revision arthroplasties in 35 patients for aseptic loosening of the humeral component with a mean 7-year follow-up (2-19.2). The mean interval from primary arthroplasty to revision was 7.1 years (0.4-16.6). Although the complications were not insignificant, they found that survival free of reoperation due to any cause was 89%. Furthermore, shoulders free of osteolytic defect at 10 years were 90.6%. The authors concluded that revision of the humeral component, with or without associated glenoid component revision or removal for aseptic loosening, was a successful procedure and could reliably provide pain relief and improve function. These results were particularly strong when the revision procedure was a TSA.9

Revision for Infection In 2001, Sperling et al.42 reported on 19 primary and 7 revision shoulder arthroplasties for infection of 2512 shoulders and an additional 7 shoulders referred from outside

24

institutions with infection. The average time from arthroplasty to the diagnosis of infection was 3.5 years (range, 0-14.8 y). The patients were divided into four groups on the basis of treatment. Group I comprised 20 patients (21 shoulders) who underwent resection arthroplasty. Six of the twenty-one shoulders had additional episodes of infection. Group II comprised six patients (six shoulders) who underwent debridement and prosthetic retention. Three of the six shoulders failed this treatment with subsequent reinfection and underwent a resection arthroplasty. Group III comprised two patients (two shoulders) who had removal of the prosthesis, debridement, and immediate reimplantation. One patient underwent resection arthroplasty 9 months after direct exchange because of reinfection. Group IV comprised three patients (three shoulders) who had removal of the prosthesis, debridement, and delayed reimplantation. Reinfection did not occur in any of these patients. Interestingly, they found that at final follow-up, patients with prosthesis had better pain relief and shoulder function than patients treated with resections. They concluded that delayed reimplantation may offer the best hope for pain relief, eradication of infection, and maintenance of shoulder function. Ince et al.22 reported on 16 patients with a one-stage reimplantation for infection. By the time of follow-up, only nine patients were available for clinical examination and assessment. The infections were largely caused by staphylococci, Propionibacterium species, and streptococci. Two were early infections (within 3 months of surgery) and 14 were late infections. The mean follow-up was 5.8 years (13 mo to 13.25 y) when the mean Constant-Murley score was 33.6 points and the mean University College of Los Angeles

25

score 18.3 points. Further revision was performed in three patients. One sustained a periprosthetic humeral fracture, another developed an acromial pseudarthrosis after transacromial surgery, and the third suffered recurrent dislocations. As no patient had a recurrence of infection, they concluded that exchange procedures using antibiotic-loaded bone cement eradicated infection in all their patients and such a procedure was at least as successful as either a resection or a two-stage exchange in the management of the infected shoulder arthroplasty. Finally, Strickland et al.43 examined 19 shoulders with twostage reimplantations for infected TSA with a minimum 2-year follow-up. There were 2 excellent, 4 satisfactory, and 13 unsatisfactory results. There were 14 complications. In only 12 of the 19 shoulders (63%), infection was considered to be eradicated. The mean pain score improved from 4.2 (3-5 [out of 5]) to 1.8 (1-4). The mean elevation improved from 42 (0140 degrees) to 89 degrees (0-165 degrees), mean external rotation from 30 (0-90 degrees) to 43 degrees (0-90 degrees), and mean internal rotation from the sacrum to L5. With these results, they suggested that two-stage reimplantation for an infected shoulder replacement was associated with a high rate of unsatisfactory results, marginal success at eradicating infection, and a high complication rate.

Revision for Instability Gerber et al. comment that reasons for instability after TSA include errors in restoration of articular anatomy, or disruption of soft tissues about the joint. Thus, revision surgery for instability can be very challenging because of difficulties in restoring normal articular position and

26

orientation, as well as reconstruction of deficient soft tissues.19 Sanchez-Sotelo et al.35 echoed the difficulty dealing with soft tissue problems and specifically instability. The purpose of their study was to review the results of revision surgery performed for the treatment of instability after shoulder arthroplasty to better define the causes and the risk factors for an unsatisfactory outcome. P.362

They examined 33 shoulders (seven of which had had a hemiarthroplasty and 26 of which had had a TSA) treated surgically for anterior instability (19 shoulders) or posterior instability (14 shoulders). The instability was attributed to abnormal capsular tension and/or RC dysfunction in 21 shoulders, component malpositioning in 1 shoulder, and a combination of both in 11 shoulders. One shoulder was treated with removal of the components. In the remaining 32 shoulders, each of the elements that were contributing to the instability was specifically addressed at the time of surgery. Revision surgery restored stability in 9 of the 32 shoulders. Anterior instability was associated with a higher failure rate than posterior instability was (P = 0.04). Although 11 shoulders had additional surgery for the treatment of recurrent instability, only 14 of the 33 shoulders were stable at the time of the final follow-up. According to the Neer rating system, there were 4 excellent, 6 satisfactory, and 23 unsatisfactory results. They concluded that surgical treatment of instability following arthroplasty was associated with only a modest success rate.

DIAGNOSTIC EVALUATION

27

It is clear from the above materials that the major problems encountered have been defined. It is also clear that several problems can coexist in the same shoulder. Information should be collected to define the etiology of difficulty or difficulties in the shoulder including prior surgical records and radiographs. One needs to obtain a careful history concerning the shoulder, other joint symptoms, and the patient's general health. Physical examination of the shoulder, the extremity, and the cervical spine should be performed. Plain radiographs of the shoulder include a 40-degree posterior oblique view in internal and external rotation plus an axillary view supplemented with a fluoroscopically positioned spot view of the glenoid when necessary. There should be consideration of adjunctive tests such as a white blood cell count with differential, C-reactive protein, and erythrocyte sedimentation rate for almost all patients with painful arthroplasties. If there is a low suspicion of infection, one might consider paired bone and indium-labeled white cell radioisotope scans to further exclude the possibility of a low-grade infection. If suspicion of infection is moderate or higher, the hematologic studies are combined with a shoulder arthrogram and aspiration. This provides the opportunity to obtain a culture, outline any fistulous tracts that might exist, as well as aid in recognizing RC tearing or identify substantial synovitis associated with particulate wear. Occasionally, dye will be seen tracking between the implant and the cement or the bone. Additionally, if there is substantial muscle weakness present, one might wish to consider electromyographic testing, particularly if the etiology of the initial shoulder problem was trauma.

28

With the above basic information and testing supplemented by adjunctive tests as necessary, one can almost always define the etiology of the pain and limitation of function, leading to implant failure and then proceed with the next step—treatment planning.

TREATMENT PLANNING As there are multiple factors that can lead to failure, it is useful to develop a revision treatment plan or a problem list. The diagnostic evaluation has found the problems, and the problems are then enumerated on this list. Among the possible solutions is the possibility that nonstandard implants will be needed or a variety of component sizes will be required that are not usually available and must be requested. Also, it is possible that additional tissue will be required, perhaps bone bank bone graft for small bone deficiencies or autogenous bone graft, if the bone defect is more critical to the structural integrity of the composite. If a small amount of autogenous bone graft is needed, bone graft from the anterior iliac crest will be adequate; if a larger amount of bone graft is necessary, posterior iliac crest graft will be needed— necessitating changing the position of the patient during the operative intervention. If soft tissue grafting is needed, one might wish to consider supplementation with autogenous fascia lata or a soft tissue allograft, such as a tendo-achilles allograft.

SURGICAL INDICATIONS The indications for surgery are similar to other reconstructive orthopaedic procedures, but the margin for error is less, and, thus, the indications for surgery must be clearly defined and understood. First, the patient must be having sufficient

29

symptoms, including pain and limitation of function, to warrant the major surgical procedure. Second, clear-cut structural deficiencies must be defined by virtue of the diagnostic evaluation and treatment planning. Third, the surgeon must have a good understanding and be able to articulate to the patient the potential benefits and the limitations of the surgery. In many situations, there are soft tissue and bone deficiencies that will preclude a high assurance of obtaining stability, improving movement, and gaining strength. These limitations should be defined. The decision to undertake surgery often hinges on the seriousness, that is, the intensity, of the pain and the amount of limitation of upper extremity function. In some situations, these limitations are so extensive that it will even be to the patient's benefit to consider a surgical procedure with only a fair chance of treatment success, as nonsurgical treatment offers no hope for improvement over time. Alternatively, some patients who are older with lower demands and who have a reasonable pain situation may well elect to defer on any further surgical treatment when the probability of gain in function is so uncertain. Integrating the level of patient symptomatology, the extent of structural abnormalities, and the information concerning outcome will lead to informed judgment.

SURGICAL TECHNIQUE Operative Exposure Almost always, the approach will take place through the deltopectoral interval. As such, the skin incision is typically vertical on the anterior aspect of the shoulder, slightly lateral to the deltopectoral interval. In revision procedures, there have, of course, been one or more preceding surgical

30

incisions. One makes every effort either to utilize the old incision or to incorporate it into a longer incision that will allow one to approach the deltopectoral interval and retract the deltoid laterally. If the old scar on the skin has spread, the widened area is excised. The deltopectoral interval is most easily developed just distal to the clavicle where there is a natural infraclavicular triangle separating the deltoid and pectoralis major muscles. One then progresses distally. When encountering the cephalic vein, the deltoid is retracted laterally, leaving the cephalic vein on the medial aspect of the exposure. In revision work, the cephalic vein may have already been ligated or may be incorporated P.363

in scar such that preservation of the vein is not possible. Otherwise, the vein is preserved and allowed to rest medially on the pectoralis major. The anterior border of the deltoid is then mobilized from the clavicle to its insertion on the humerus, and often the anterior portion of the insertion is elevated slightly, in continuity with the more distal periosteum of the humerus. Scarring may be less intense inferiorly, and, as such, the plane between the deltoid and the humerus can be identified there. Scarring is often most intense over the midportion of the anterior deltoid. This is a very dangerous area as the branches of the axillary nerve lie on the undersurface of the deltoid muscle, and one must be meticulous in the dissection. After identifying the plane distally, it may be wise to discontinue the distal-toproximal elevation of the deltoid and to return to the upper portion of the deltoid elevating this portion and exposing the undersurface of the acromion. One can then incise the tissue

31

adherent to the undersurface of the acromion and develop the interval between the acromion and humeral head. Typically, this plane can be extended posteriorly where scarring is less and then advanced laterally and anteriorly, completing the elevation of the deltoid off the upper humerus. Occasionally, the scar is so dense and the tissue planes so obscure that this technique will not suffice. Also, the deltoid might be quite thin and frail. In these circumstances (perhaps 5%-10% of revision cases), the deltoid origin is incised from the clavicle, acromioclavicular joint, and anterior aspect of the acromion and carefully reflected laterally—to be repaired at the end of the procedure. If the deltopectoral exposure can be accomplished, the deltoid is held laterally with either a Richardson retractor or a Brown-like deltoid retractor. The next step in developing this plane is to identify the conjoined tendon group and develop the plane between the subscapularis muscle and this group. The arm is placed in as much external rotation as possible. Usually, scarring is less just distal to the coracoid, and dissection can then progress from superior to inferior and from lateral to medial to develop this interval. If there is excellent external rotation, extensive development of this interval is not necessary; unfortunately, external rotation is often limited, and freeing the subscapularis from scar is an important part of the procedure. Dissection in this area must be done very carefully because of the neurovascular group, the axillary nerve, and the musculocutaneous nerve. As such, dissection in this area may take a few minutes or it may take a considerable amount of time to accomplish what needs to be done to free the subscapularis. Scar is then released from around the base of

32

the coracoid, and the shoulder is examined for range of motion. If motion in abduction is limited below 130 or 140 degrees, one can anticipate the need for release of the inferior shoulder capsule. If external rotation is less than 30 degrees, it is probably prudent to incise the subscapularis from the upper humerus rather than incising it through its tendinous substance. Internal rotation is noted. The lower portion of the rotator interval between the subscapularis and supraspinatus is then incised with great care to avoid injury to the long head of biceps tendon. The subscapularis and anterior shoulder capsule are then elevated from the humerus if there is substantially limited external rotation, or the incision is made through the tendinous substance of the subscapularis, just medial to the humeral capsule, insertion, if external rotation is ample. This incision is then continued inferiorly when abduction is limited so that one can carefully incise the inferior shoulder capsule from the neck of the humerus. This is accomplished by proceeding from anterior to posterior with progressive external rotation of the humerus and by careful use of electrocautery so that one can avoid inadvertent encounter with the axillary nerve. When there is limitation of abduction, typically the inferior shoulder capsule is released to the area of the teres minor. Following removal or retraction of the prosthetic humeral head (as will be addressed later), the upper humerus is retracted lateralward and the joint is inspected. Hypertrophic synovium is debrided. This aids measurably in defining the shoulder capsule. Typically, the anterior-superior shoulder capsule is released from noon to approximately the 3 o'clock position on a right shoulder with the incision then extending

33

laterally along the superior border of the superior band of the inferior glenohumeral ligament. An elevator can then be placed beneath this portion of the anterior shoulder capsule and the subscapularis partially freeing these structures from the anterior aspect of the scapula allowing greater mobility of the anterior soft tissue sleeve and, hence, improved external rotation. It is seldom necessary to release the posterior shoulder capsule. However, in certain very tight shoulders or occasionally in those shoulders in which the humeral head implant cannot be removed easily, the posterior shoulder capsule is incised along the glenoid rim. The humerus is then retracted posteriorly and held there with a Fukuda-like ring retractor, a modified Hohmann-humeral neck retractor, or a large broad elevator. To facilitate exposure to the glenoid, the arm is typically placed in 70 to 80 degrees of abduction, neutral flexion-extension, and rotated to find the best position for the remaining humeral head and neck behind the retractor. With careful, gentle, but persistent pressure, one can almost always retract the humerus posteriorly enough to expose the glenoid.

THE HUMERAL COMPONENT After completion of the arthrotomy and release of the inferior capsule that is usually required, the humerus is subluxated forward by placing an elevator along the posterior-inferior aspect of the humeral head. The arm is positioned in slight extension, in adduction, and then progressively externally rotated. Care must be taken in the amount of torque placed on the humeral shaft to avoid humeral shaft fractures. The RC attachment is then defined superiorly and posteriorly. The surface of the humeral component is assessed for any wear

34

or other material imperfections, and position is determined. Typically, the height of the prosthetic humeral head will be slightly above that of the greater tuberosity. The varus-valgus position of the humeral head is noted relative to the tuberosities and the humeral shaft. The size of the humeral head is evaluated relative to the anticipated size of the patient's usual humeral head with recognition of the flexibility of the soft tissue envelope determined during exposure. Rotation of the implant is then assessed in relation to the flexed forearm. By evaluating all these things, the humeral surface characteristics, the height, the varus-valgus positioning (also anterior-posterior positioning), head size and rotation, one can have a good sense about whether or not the humerus will need to be changed. Attention is then directed to the fixation within the humeral shaft with an eye toward the need for glenoid work. If there is a one-piece, uncemented humeral implant, the implant is usually removed. If there is a modular humeral head, this is disarticulated. If there is a one-piece humeral prosthesis that is cemented in good position, quite typically this is left in place and is retracted posteriorly as best as possible. If there is a onepiece humeral prosthesis that is cemented in place in poor position, the implant must be removed. Occasionally, it is possible to crack the cement surrounding the upper portion of the implant and then to extract the implant, either by impaction or by use of a humeral component extractor. Many times, however, the stem is so securely cemented in the humerus that this is not possible. The large size of the humeral head usually precludes effective cement removal from the diaphyseal area of the humerus via the upper P.364

35

portion of the humeral canal. One will need to make a window in the humerus on its anterolateral aspect, usually about a centimeter in diameter and extending from approximately 3 cm below the cut in the humeral neck to near the end of the cement surrounding the humeral implant. This long, narrow, cortical window is then elevated, cement can be removed from within the humeral canal and around the humeral component, and the component can then be impacted from the humerus. Additional cement removal then ensues, and the remaining humeral bone is prepared, often with careful use of a high-speed, low-torque burr. When a new component is placed, it must be long enough to bypass the window by two to three centimeters, and the window is held in place with cerclage, cables, or heavy sutures. Additional bone graft can be placed surrounding the window if that is felt to be necessary. Some modular systems will allow the creation of slight offset of the humeral head or placement of a slightly eccentric humeral head on the stem to accommodate for some variation in varus, valgus, or anterior-posterior placement, or aberrant rotational placement of the implant system. If correction in position of a modular system cannot be accomplished, it will be necessary to remove the stem of the modular humeral component. Unfortunately, a number of these components have rather aggressive texturing or tissue-ingrowth capabilities extending down the stem of the component, either to the metaphyseal area or, unfortunately, to the diaphyseal area. These components are extremely difficult to remove, quite likely requiring the humeral window and also very careful use of a high-speed burr to try to cut the interval

36

between the implant and the bone. It is indeed an accomplishment to change such a component without creating any fractures of the humerus. In line with this, after removing a humeral component, it is wise to place a humeral stem trial within the humerus before retracting the humerus posteriorly, to guard against inadvertent humeral fracturing. Following completion of work on the glenoid, a humeral component is then repositioned. If a modular system is used and the stem is fixed in good position, adjustment in head size is easily possible. If a new stem needs to be secured, it will be unlikely that enough metaphyseal and diaphyseal bones will be present in the amount and quality required to seat a pressfitted or tissue-ingrowth component. As such, adjunctive bone cement will be necessary. There are a variety of philosophies about how to use bone cement in securing a humeral component in the revision setting. Our personal preference is to plug the canal, to lavage the canal, to use a cement gun, and then to use finger pressure for pressurization. The component is then carefully seated in the new cement bed.

THE GLENOID COMPONENT Following retraction of the humerus posteriorly, scar tissue is excised from around the glenoid component. The surface is then assessed for any wear or deformity. The position is assessed, superior-inferior, anterior-posterior, rotational, and angulatory relative to anteversion and retroversion. A lever is carefully applied to the edge of the glenoid component, and the integrity of glenoid fixation is assessed. If the glenoid is grossly loose, of course, it is removed; if there is a moderate amount of loosening, additional tissue is removed from the

37

interface, and the glenoid is carefully levered away from the underlying bone. If the component is loose but is not easily disengaged from the bone of the glenoid, it may be necessary to divide the polyethylene surface of the glenoid component and to then fracture underlying, interlocking bone cement. If there is metal-backing to the polyethylene, the problem is intensified. One often has to work around the edges of the metal to free the component from the underlying bone. Some metal-backed polyethylene components have holes in the center of the metal plate, allowing removal of the polyethylene and working through the holes in the metal plate to facilitate component removal. Fortunately, most tissueingrowth glenoid components have the majority, if not all, of the tissue-ingrowth surface overlying the face of the glenoid, with very little extending into the glenoid neck. As such, one can use a narrow, slightly curved osteotome to undermine the metal backing of these types of glenoid components, remove any screws that are present, and then extract the component. Needless to say, one must take great care in removing a slightly loosened glenoid component, because the bone of the glenoid is small in amount and often frail in character. Almost any amount of fracturing of the native glenoid will preclude secure replacement of a subsequent glenoid component. Following removal of the old glenoid component, one is typically left with intact glenoid rims but with a central cavity of varying size. If the central cavity is large and the walls of the glenoid neck are frail, it is probably a better choice to fill this cavity with bone graft and not to place a new glenoid component for fear that loosening will occur in a very short period of time. On the other hand, if the size of the cavity is small, the bone can be prepared, and a new polyethylene

38

component can be cemented in place. If the cavity is medium in size, one might wish to consider a variation of the Ling technique for the femoral shaft; that is, impacting corticocancellous bone into the defect and then preparing the glenoid for implantation of either a keeled or a columned type device. Our personal preference in this setting has been to prepare the glenoid for a columned-type device and to bypass the bone graft with these columns and screws, allowing the surface of the implant to rest on a mixture of native and bone graft bone. Usually, bone cement fixation is also used, but occasionally it may not be. It is important to recognize that glenoid components now come in a variety of sizes and shapes to aid in correcting special problems that are encountered at the time of revision surgery. Components vary in thickness from 4 to 12 mm, and some components have eccentric configurations to correct for slight abnormalities in glenoid position, and, as mentioned above, come in both keel-shaped and column-shaped variants so that one can address a variety of local anatomic changes that are encountered. Careful preoperative planning is necessary to be assured that one has the variety of glenoid components needed to address the spectrum of bone deficiencies encountered. Rarely, in addition to central bone deficiency, there is a peripheral or rim deficiency. Often, scar has filled the area, and the adjacent shoulder capsule is density adherent over this region precluding the need to place supporting materials to attain shoulder stability. When, however, there is a substantial peripheral rim defect and stability cannot be attained by virtue of adaptations in the soft tissues, one must consider grafting the defect. Almost always, this will require

39

iliac crest bone grafting with screw fixation into the remaining glenoid neck and the very firm bone at the junction between the glenoid neck and body of the scapula. After fixing the structural graft in place, one can then again entertain the decision as to whether or not a glenoid component should be placed on top of this.

SOFT TISSUE REPAIR After addressing the glenoid difficulties and repositioning the humeral head, one then can consider the repair methodology for the RC and shoulder capsule.4 As a part of the exposure and during the procedure, the coracoacromial arch is inspected P.365

and preserved, if possible. Any gross irregularities in the shape of the undersurface of the acromion or distal clavicle are smoothed. The RC is assessed by observation and palpation, both on its outer and inner aspects. During trial reductions, the stability of the humerus against the glenoid is determined, and adjustments in humeral head size are made. The subscapularis is then repaired. If it was removed from bone, it is sutured to bone through drill holes in the humeral neck. If this type of subscapularis repair is done, it is often helpful to place the sutures before seating the new humeral implant. If the humeral stem was not removed at the time of revision, it is often useful to place burr holes through the humeral cortex on the anterior neck and then to pass sharp, cutting needles through the metaphyseal bone. If the arthrotomy was through tendinous tissue, of course, the tendons are again sutured. It is very important to obtain

40

secure closure of the interval area. It has been our experience that many of the failures of anterior repair are through this region and do not include substantial disruption of the vertical portion of the subscapularis repair. After closure of the arthrotomy, the shoulder is taken through a range of motion. Translation of the humeral head is assessed anteriorly, posteriorly, and inferiorly, and, if all is reasonable, the amount of motion obtained is recorded. This will then allow passive motion to occur within these motion limits until tissue healing is moderately firm, usually at 4 to 8 weeks— often about 6 weeks. Occasionally, gentle isometric type strengthening can be started before the 6-week period, but often it is prudent to delay strengthening until early soft tissue healing has occurred.

SPECIFIC PROBLEMS There can, of course, be bone deficiencies underlying both the humeral and glenoid components.5 Commonly, the bone deficiency of the upper humerus is in the form of metaphyseal bone loss. It is usually addressed by use of fixation with bone cement. Occasionally, due to trauma or fracturing, a portion of the upper humerus is absent. This has been addressed in three ways. The first is by bone grafting the deficiency. This is usually for small- to medium-sized bone deficiencies. The second is through the use of an allograft humerus through which a humeral component has been placed. The third is the use of a custom prosthesis that replaces a portion of the upper humerus and relies on the formation of adjacent scar to attain stability, albeit with substantial weakness. Small amounts of glenoid deficiency can usually be addressed with the use of bone cement. Larger deficiencies require some

41

form of bone grafting. If the area involved is not very important to structure and stability, allograft is probably the most useful choice. If there is an area of structural importance that needs to be replaced or bone healing is definitely required for maintaining glenoid fixation, autograft bone would be preferred. Instability following TSA is a serious problem.7 Unfortunately, the cause of instability is usually not unifactorial and easily addressed, such as the uncommon situation of anterior instability associated with a subscapularis rupture. Often, the problem is more complex, and multiple factors are involved. It is, of course, important to determine the direction or directions and degree of instability, not only in the office but also with examination under anesthesia. One needs to know if the RC is intact or not. If this is not clear during preoperative evaluation, a shoulder arthrogram may be of some value. The position and size of the components need to be carefully determined. Hopefully, at the time of revision surgery, soft tissue abnormalities can be corrected to recreate stability, but, all too often, one or both of the components need to be changed. If there is posterior instability and the glenoid is retroverted, of course, that will need to be corrected. If there is anterior stability and the glenoid is anteverted, that will need to be addressed. If there is posterior instability with the glenoid in good position and the tension across the superior and anterior portions of the RC is as one would wish but the posterior structures are too loose, the posterior structures will need to be tightened. If there is inferior instability and the humeral component has been placed too low in the humerus, the component will need to be placed more superior relative to the humerus, and, quite likely, additional bone graft will

42

need to be added. Instability following shoulder arthroplasty occurs in all directions and is sometimes even multidirectional. It is very important to do detailed preoperative analysis and be prepared to vary the approach to postarthroplasty instability, according to the specific abnormalities that can be defined. The need to perform revision surgery for RC tearing is surprisingly uncommon. There are, of course, individuals who have shoulder arthroplasty who subsequently have a dramatic change in shoulder function associated with a rather mild injury. In these settings, it is useful, as in patients who do not have a shoulder arthroplasty, to perform a careful physical examination, to decide whether or not a substantial RC tear has occurred, and to consider an early repair if there has been a dramatic change in shoulder function. Usually, however, RC problems present in a similar manner to those patients without a shoulder arthroplasty. That is, the patients have chronic, rather long-term symptoms. Evaluation suggests tearing of the supraspinatus or supraspinatus and infraspinatus tendons. There may or may not be substantial pain associated with the presence of these tears, but strength is diminished and active motion may be reduced. In these settings, it is important to identify as best as possible the magnitude of the tendon tearing and to consider whether or not reconstructive tendon surgery would be of benefit. Often in this setting, it does not seem that it will help dramatically. The pain is somewhat less than the usual patient who present with RC tearing, and the promise for increased function following revision surgery is somewhat less certain. If RC repair following arthroplasty is undertaken, it will be somewhat more difficult than the usual RC repair. If the

43

shoulder is reasonably stable and one is convinced that the anterior and posterior structures are intact, one might use an anterior-superior approach to the shoulder, address the coracoacromial arch as is typical for RC surgery, and perform a direct repair of the tendon. If direct tendon repair is not possible, some form of grafting will be necessary. This could be either autogenous fascia lata graft or perhaps an allograft tendon. Fortunately, this type of surgery is rarely required.

COMPLICATIONS AND LIMITATIONS OF REVISION SURGERY The scientific information in regard to expected outcomes and the limitations of shoulder arthroplasty revision surgery is slowly building. Some general guidelines are available. Material to date suggests that should glenoid arthropathy develop in humeral head replacement, placing a glenoid component usually eliminates pain.10 If there is a loosened glenoid component that requires revision surgery, somewhere between one half and two thirds of these components can be successfully revised. The remaining one half to one thirds will have such substantial bony deficiencies that only bone grafting the defect P.366

will be possible.1 When the humeral component loosens and revision surgery is necessary, revision can typically be successfully performed using slightly longer-stemmed components and having fixation supplemented with bone cement. If there are specific identifiable factors leading to shoulder instability, such as component malposition or disruption of healthy soft tissues, revision surgery to correct

44

instability will quite likely be successful. If the instability is associated with vague factors, often compounded by inadequate soft tissues, including the RC tendons, revision surgery is unlikely to be dramatically successful. Certainly, limited goals rehabilitation will be needed, and, as such, the outcome can be anticipated to be fair at best. When a RC tear occurs in a rather acute mode, it is quite likely that tendon repair will be sufficiently helpful to warrant revision surgery. When chronic attrition ensues, the likelihood of success with larger sized tears is lessened.

FIGURE 38.2 A: Example of a patient with an infected TSA with a loose glenoid component. B: The patient underwent component removal with placement of antibiotic-impregnated cement beads. The patient subsequently underwent reimplantation of a hemiarthroplasty 3 months following resection with placement of antibiotics in the cement.

45

A fracture beneath a humeral prosthesis is usually addressed by immobilization and observation if a satisfactory reduction can be obtained. If the fracture does not progress toward healing, then in 2 to 4 months, one would quite likely consider open reduction and fixation with the use of a plate, cerclage, and bone grafting. Of course, if the fracture involves a substantial portion of the fixation of the humeral component, revision surgery will be needed that includes revision of the humeral component to a long-stemmed component, possibly additional cerclage fixation, and, quite likely, autogenous bone grafting. There is not a large amount of information available on the treatment of infection following shoulder arthroplasty.42 Certainly, classic treatment is removal of the components and any bone cement. The articulation is then treated as a resection arthroplasty with rest until stiffening occurs and then gentle stretching and strengthening. It is suggested that about one half to two thirds of patients so treated achieve a satisfactory pain state, and movement and strength will approximate one third normal. This form of treatment is probably still the first line of treatment for patients with extensive infection and osteomyelitis that extends through many areas of the humerus. However, for those patients presenting with largely an infectious arthritis picture and only mild changes in the bone, they will probably benefit from removal of the components, debridement of the tissues, and a delayed reimplantation of either the humerus or the humerus and the glenoid components (Fig. 38.2). There is little information about primary exchange or about treatment of acute joint infections with debridement and antibiotics. The exact guidelines for treatment of the infected shoulder

46

arthroplasty are still unclear but will likely mirror the guidelines being formulated for the treatment of infections following hip and knee arthroplasty.

SUMMARY To effectively undertake revision TSA, one must have an understanding of shoulder disease, information about the original operative procedure, detailed knowledge about the current situation in the shoulder, understand the patient, define reasonable treatment options, be prepared for the technical variations encountered during the operative procedure, and recognize the limitations of this type of surgery. The literature suggests that revision arthroplasty is indeed uncommon, approximating 3% of a large number of shoulder arthroplasties that have been performed and reported. Undoubtedly, though, revision is needed somewhat more commonly than this. The causes of failure are well defined. Unfortunately, they are often multifactorial in a single shoulder. As such, the shoulder must be carefully analyzed, the various problems defined, and the treatment planning meticulous. Surgical indications must take into account the real benefits but perhaps more importantly the real limitations, of these procedures. The revision procedure itself will usually be technically challenging, will often require adjunctive bone grafting, addressing soft tissue contractures or deficiencies, and placement of components that are somewhat unusual in size or ordered specifically for the patient. All these complexities are compounded by the absence of an ample body of science describing the outcomes of this type of surgery. Only now is this being pieced together. It is quite likely that a decade from now our

47

understanding will be much more complete—and our armamentarium for treatment will be increasingly satisfactory. P.367

References 1. Antuna SA, Sperling JW, Cofield RH, Rowland CM: Glenoid revision surgery after total shoulder arthroplasty. J Shoulder Elbow Surg 10(3): 217-224, 2001. 2. Boileau P, Watkinson D, Hatzidakis AM, Hovorka I: Neer Award 2005: The Grammont reverse shoulder prosthesis: Results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 15(5):527-540, 2006. 3. Braman JP, Falicov A, Boorman R, Matsen FA III: Alterations in surface geometry in retrieved polyethylene glenoid component. J Orthop Res 24(6):1249-1260, 2006. 4. Carroll RM, Izquierdo R, Vazquez M, et al: Conversion of painful hemiarthroplasty to total shoulder arthroplasty: Longterm results. J Shoulder Elbow Surg 13(6):599-603, 2004. 5. Chacon A, Virani N, Shannon R, et al: Revision arthroplasty with use of a reverse shoulder prosthesisallograft composite. J Bone Joint Surg Am 91(1):119-127, 2009. 6. Cheung EV, Sperling JW, Cofield RH: Polyethylene insert exchange for wear after total shoulder arthroplasty. J Shoulder Elbow Surg 16(5):574-578, 2007. 7. Cheung EV, Sperling JW, Cofield RH: Reimplantation of a glenoid component following component removal and allogenic bone-grafting. J Bone Joint Surg Am 89(8):17771783, 2007.

48

8. Cheung EV, Sperling JW, Cofield RH: Revision shoulder arthroplasty for glenoid component loosening. J Shoulder Elbow Surg 17(3):371-375, 2008. 9. Cil A, Veillette CJ, Sanchez-Sotelo J, et al: Revision of the humeral component for aseptic loosening in arthroplasty of the shoulder. J Bone Joint Surg Br 91(1):75-81, 2009. 10. Codsi MJ, Bennetts C, Powell K, Iannotti JP: Locations for screw fixation beyond the glenoid vault for fixation of glenoid implants into the scapula: An anatomic study. J Shoulder Elbow Surg 16(3 Suppl):S84-S89, 2007. 11. De Wilde L, Mombert M, Van Petegem P, Verdonk R: Revision of shoulder replacement with a reversed shoulder prosthesis (Delta III): Report of five cases. Acta Orthop Belg 67(4):348-353, 2001. 12. Deutsch A, Abboud JA, Kelly J, et al: Clinical results of revision shoulder arthroplasty for glenoid component loosening. J Shoulder Elbow Surg 16(6):706-716, 2007. 13. Dines JS, Fealy S, Strauss EJ, et al: Outcomes analysis of revision total shoulder replacement. J Bone Joint Surg Am 88(7):1494-1500, 2006. 14. Elhassan B, Ozbaydar M, Higgins LD, Warner JJ: Glenoid reconstruction in revision shoulder arthroplasty. Clin Orthop Relat Res 466(3):599-607, 2008. 15. Fevang BT, Lie SA, Havelin LI, et al: Risk factors for revision after shoulder arthroplasty: 1,825 shoulder arthroplasties from the Norwegian Arthroplasty Register. Acta Orthop 80(1):83-91, 2009. 16. Fox TJ, Cil A, Sperling JW, et al: Survival of the glenoid component in shoulder arthroplasty. J Shoulder Elbow Surg 18(6):859-863, 2009.

49

17. Frankle M, Levy JC, Pupello D, et al: The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. a minimum two-year follow-up study of sixty patients surgical technique. J Bone Joint Surg Am 88(Suppl 1 Pt 2):178-190, 2006. 18. Gagey O, Pourjamasb B, Court C: Revision arthroplasty of the shoulder for painful glenoid loosening: A series of 14 cases with acromial prostheses reviewed at four year follow up. Rev Chir Orthop Reparatrice Appar Mot 87(3):221-228, 2001. 19. Gerber A, Ghalambor N, Warner JJ: Instability of shoulder arthroplasty: balancing mobility and stability. Orthop Clin North Am 32(4):661-670, 2001, ix. 20. Hattrup SJ: Revision total shoulder arthroplasty for painful humeral head replacement with glenoid arthrosis. J Shoulder Elbow Surg 18(2):220-224, 2009. 21. Holcomb JO, Cuff D, Petersen SA, et al: Revision reverse shoulder arthroplasty for glenoid baseplate failure after primary reverse shoulder arthroplasty. J Shoulder Elbow Surg 18(5):717-723, 2009. 22. Ince A, Seemann K, Frommelt L, et al: One-stage exchange shoulder arthroplasty for peri-prosthetic infection. J Bone Joint Surg Br 87(6):814-818, 2005. 23. Kumar S, Sperling JW, Haidukewych GH, Cofield RH: Periprosthetic humeral fractures after shoulder arthroplasty. J Bone Joint Surg Am 86-A(4):680-689, 2004. 24. Neyton L, Boileau P, Nove-Josserand L, et al: Glenoid bone grafting with a reverse design prosthesis. J Shoulder Elbow Surg 16(3 Suppl):S71-S78, 2007. 25. Neyton L, Sirveaux F, Roche O, et al: Results of revision surgery for glenoid loosening: A multicentric series of 37

50

shoulder prosthesis. Rev Chir Orthop Reparatrice Appar Mot 90(2):111-121, 2004. 26. Neyton L, Walch G, Nove-Josserand L, Edwards TB: Glenoid corticocancellous bone grafting after glenoid component removal in the treatment of glenoid loosening. J Shoulder Elbow Surg 15(2):173-179, 2006. 27. Nho SJ, Nam D, Ala OL, et al: Observations on retrieved glenoid components from total shoulder arthroplasty. J Shoulder Elbow Surg 18(3): 371-378, 2009. 28. Nystuen CM, Leopold SS, Warme WJ, Simmons GE: Cancellous impaction and cortical strut allografting for revision shoulder arthroplasty: A case report. J Shoulder Elbow Surg 15(2):244-248, 2006. 29. Phipatanakul WP, Norris TR: Treatment of glenoid loosening and bone loss due to osteolysis with glenoid bone grafting. J Shoulder Elbow Surg 15(1):84-87, 2006. 30. Piper KE, Jacobson MJ, Cofield RH, et al: Microbiologic diagnosis of prosthetic shoulder infection by use of implant sonication. J Clin Microbiol 47(6):1878-1884, 2009. 31. Ramsey ML, Fenlin JM Jr: Use of an antibioticimpregnated bone cement block in the revision of an infected shoulder arthroplasty. J Shoulder Elbow Surg 5(6):479-482, 1996. 32. Ravenscroft M, Charalambous CP, Haines JF, Trail IA: Outcome of stemmed shoulder hemi-arthroplasty revision. Arch Orthop Trauma Surg 129(6):797-799, 2009. 33. Rice RS, Sperling JW, Miletti J, et al: Augmented glenoid component for bone deficiency in shoulder arthroplasty. Clin Orthop Relat Res 466(3):579-583, 2008. 34. Rozing PM: A posterosuperior approach to the shoulder. J Shoulder Elbow Surg 17(3):431-435, 2008.

51

35. Sanchez-Sotelo J, Sperling JW, Rowland CM, Cofield RH: Instability after shoulder arthroplasty: Results of surgical treatment. J Bone Joint Surg Am 85-A(4):622-631, 2003. 36. Scalise JJ, Iannotti JP: Bone grafting severe glenoid defects in revision shoulder arthroplasty. Clin Orthop Relat Res 466(1):139-145, 2008. 37. Scalise JJ, Iannotti JP: Glenohumeral arthrodesis after failed prosthetic shoulder arthroplasty. Surgical technique. J Bone Joint Surg Am 91 Suppl 2(Pt 1):30-37, 2009. 38. Scarlat MM, Matsen FA III: Observations on retrieved polyethylene glenoid components. J Arthroplasty 16(6):795801, 2001. 39. Seitz WH Jr, Damacen H: Staged exchange arthroplasty for shoulder sepsis. J Arthroplasty 17(4 Suppl 1):36-40, 2002. 40. Sirveaux F, Favard L, Oudet D, et al: Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br 86(3):388-395, 2004. 41. Sperling JW, Cofield RH: Humeral windows in revision shoulder arthroplasty. J Shoulder Elbow Surg 14(3):258-263, 2005. 42. Sperling JW, Kozak TK, Hanssen AD, Cofield RH: Infection after shoulder arthroplasty. Clin Orthop Relat Res 382:206-216, 2001. 43. Strickland JP, Sperling JW, Cofield RH: The results of two-stage reimplantation for infected shoulder replacement. J Bone Joint Surg Br 90(4): 460-465, 2008. 44. Topolski MS, Chin PY, Sperling JW, Cofield RH: Revision shoulder arthroplasty with positive intraoperative cultures:

52

The value of preoperative studies and intraoperative histology. J Shoulder Elbow Surg 15(4):402-406, 2006. 45. van de Sande MA, Brand R, Rozing PM: Indications, complications, and results of shoulder arthroplasty. Scand J Rheumatol 35(6):426-434, 2006. 46. Van Thiel G, Piasecki D, Nicholson GS: Vertical humeral osteotomy for revision of well-fixed humeral components: case report and operative technique. Am J Orthop 38(2):6771, 2009. 47. Walch G, Wall B, Mottier F: Complications and revision of the reverse prosthesis: A multicenter study of 457 cases. In Walch G, BP, Mole D, et al. (eds) Reverse Shoulder Arthroplasty: Clinical Results, Complications, Revisions. France, Montpellier, 2006, pp. 335-342. 48. Wall B, Nove-Josserand L, O'Connor DP, et al: Reverse total shoulder arthroplasty: A review of results according to etiology. J Bone Joint Surg Am 89(7):1476-1485, 2007. 49. Werner CM, Steinmann PA, Gilbart M, Gerber C: Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total shoulder prosthesis. J Bone Joint Surg Am 87(7):14761486, 2005. 50. Wright TW, Cofield RH: Humeral fractures after shoulder arthroplasty. J Bone Joint Surg Am 77(9):1340-1346, 1995.

53

Chapter 39 Alternative Procedures to Prosthetic Shoulder Arthroplasty: Synovectomy, Interposition, Resection, Arthrodesis Joaquin Sanchez-Sotelo Robert H. Cofield

INTRODUCTION Before prosthetic shoulder arthroplasty, several nonprosthetic procedures were developed to address a variety of conditions in the shoulder. The indications for these alternative procedures have become considerably narrowed. Nonetheless, these nonprosthetic alternatives are quite useful in selected patients and familiarity with them allows the management a vast array of shoulder diseases and injury.

SYNOVECTOMY Synovectomy of the shoulder joint has its greatest application in the management of inflammatory arthritic conditions such as rheumatoid arthritis. In patients with an inflammatory arthritic process who present with symptoms and signs of obvious interarticular shoulder inflammation but who have a congruent joint surface without full-thickness cartilage loss, pain may be reduced by synovectomy as the pain is often attributable to this profound synovial inflammation. Contemporarily, advances in the medications for rheumatoid diseases have severely diminished the frequency of the need for this procedure for patients in this stage of their disease. Synovectomy may also be considered for patients with 1

uncommon primary synovial conditions, such as pigmented villonodular synovitis26 or synovial chondromatosis.25 , 49 In addition, synovectomy may be part of the arthroscopic debridement procedures proposed by some authors for the treatment of early arthritis in younger patients. Surgery when performed in an open manner typically is by the deltopectoral approach with an arthrotomy made by releasing the subscapularis and anterior shoulder capsule. The anterior, inferior, and superior aspects of the joint are easily debrided through this approach. The majority of the posterior aspect of the shoulder can be debrided by use of a variety of retractors including a Fukuda retractor and Ferris-Smith resectors. The shoulder must be protected following this type of approach to synovectomy to allow the subscapularis to heal. Synovectomy, when performed arthroscopically, is less invasive, allows a more complete synovectomy, and also offers the advantage of faster rehabilitation. Series of shoulder synovectomy have been reported by several authors from Scandinavia. Vainio50 performed synovectomy for rheumatoid arthritis in 18 shoulders and achieved pain relief in 12. Pahle31 , 32 reported on 54 open synovectomies for rheumatoid arthritis, 26 with advanced radiographic changes at an average 5.3-year follow-up, 44 patients had no significant pain, range of motion improved slightly, progressive radiographic deterioration was demonstrated in 12 shoulders and 6 shoulders had required prosthetic shoulder arthroplasty. Smith et al.44 reported the Mayo Clinic experience in 16 rheumatoid shoulders managed with arthroscopic synovectomy and followed for an average of 5.5 years. Pain and motion were improved, and all but three shoulders were rated as excellent or satisfactory, despite

2

radiographic progression of the disease. A large proportion of satisfactory results have also been reported when arthroscopic synovectomy is performed for the treatment of primary synovial diseases.25 , 49

INTERPOSITION Interposition of soft tissue material has been used with some success for the treatment of arthritis in other joints such as the thumb carpometacarpal joint51 or the elbow.24 Soft tissue interposition has also been considered for the shoulder either as an isolated procedure2 , 3 or combined with humeral head replacement.22 Shoulder arthroplasty, despite being reliable, may be complicated by implant mechanical failure, especially in young, active patients on the glenoid side of the joint.45 Interposition may be viewed as a temporary procedure to provide pain relief in patients with arthritis and relative contrain-dications for shoulder arthroplasty. Various materials have been proposed for shoulder interposition, including anterior capsule, autogenous fascia lata, allograft tendon or meniscus, and synthetic materials.1 , 2 , 3 , 5 , 13 , 15 , 22 Isolated interposition may be performed through an open or arthroscopic approach.2 , 3 , 13 When combined with humeral hemiarthroplasty, interposition is performed through the standard deltopectoral approach. The soft tissue material is fixed to the glenoid surface with either transosseous sutures or anchors, usually after debridement of any remaining cartilage and bone contouring.3 , 22 There is limited published information regarding the outcome of these procedures. Fink et al.13 reported a series of 53 inflammatory shoulders treated with resection-interposition

3

arthroplasty and followed for an average of 8 years. Despite acceptable early postoperative results, there was progressive joint degeneration and poor outcomes in patients with longer follow-up. Most publications on isolated interposition for osteoarthritis provide no information about patient outcome. P.369 Krishnan et al. 7 2 2 have reported a series of 36 shoulders managed with humeral head replacement combined with biologic glenoid resurfacing using anterior capsule (7), autogenous fascia lata (11), or Achilles tendon allograft (18). Results were graded as satisfactory in all but five patients. Average glenoid erosion was more than 5 mm, but appeared to stabilize after 5 years. Complications included infection (2) and instability (3). Improvements in implant design and surgical technique have translated into very good outcomes after total shoulder arthroplasty, even in younger patients.33 In our current practice, interposition has a very limited role for the treatment of exceptionally active patients, with moderate glenohumeral osteoarthritis, interested in biologic solutions and avoidance of implants.

RESECTION Resection arthroplasty can involve resection of the humeral head with or without rotator cuff repair. It can also involve resection of the glenoid or both the humeral head and the glenoid. The latter two of these three procedures are not considered currently. From a historical perspective, Steindler47 cited a 1916 report by Nove-Joserand of 237 shoulder joint resections related to

4

war injuries. After surgery, the shoulder became stable with limited or fair mobility in 45%, was flail in 38%, and became ankylosed in 11%. Steindler also reported on Garre's experience with 105 humeral head resections, 76 produced a “final cure.” Much of the literature on this procedure is related to the treatment of severe fracture-dislocations.28 , 48 Mason27 reported on 21 such procedures with the result being fair in 9 and improved in 10. Jones in 193318 and 194219 reported on three cases but introduced the concept of stabilizing the proximal end of the humerus by attaching the rotator cuff muscle tendon units to the remaining bone. In his experience, pain relief occurred, and stability was achieved as was 90 degrees of active abduction. The use of this technique was reported by Knight and Mayne21 in eight shoulders. The results were satisfactory in three, unsatisfactory in one and overt failures in four. Continuing along these lines Neer et al.30 in 1953 reported on 19 cases. The results were satisfactory in 14. He noted that during the early postoperative months the shoulder was flail. With time the motion became restricted by fibrosis or ossification and actually five of the shoulders fused. Using adjunctive procedures for the rotator cuff did not seem to improve his results. In 1978, Copeland et al.9 reported on nine shoulders that had failed prosthetic arthroplasty, essentially resulting in a resection. Pain was diminished in eight, active elevation averaged 55 degrees, external rotation 10 degrees. The authors commented that resection in this situation seemed to be no better than primarily excision arthroplasty. At the Mayo Clinic between 1950 and 1981, 10 patients without neoplasms were treated by humeral head resections.

5

Postoperatively three had no pain, five had slight pain, one had moderate pain, and one had severe pain. Active abduction averaged 55 degrees; external rotation averaged 0 degrees. Seven patients felt they had been improved by the operation; three felt there was no change.8 More recently, we reported on resection arthroplasty in 18 shoulders.37 The indications were for failed shoulder replacement in 17, with infection in 13 and chronic septic arthritis in 1. There were two intraoperative fractures that healed. The level of pain was significantly reduced, but five continued to have moderate to severe pain. Mean active elevation was 70 degrees, mean external rotation to 31 degrees. On the 12-question Simple Shoulder Test, the mean number of positive answers was 3.1. The mean American Shoulder and Elbow Surgeon's score was 36. These results seemed similar to the early results reported in the literature for patients with severe fracture-dislocation. An important reduction of pain occurred in approximately two thirds of the patients. Infection was almost always eliminated. The shoulder was comfortable with the arm at the side, but there were profound functional limitations. A similar contemporary report4 of seven shoulders undergoing this procedure for infection after shoulder arthroplasty reported moderate activity-related pain in two, elimination of infection, average forward flexion of 28 degrees, average external rotation of 8 degrees, the ability of all the patients to reach their mouths, their contralateral axilla, their back pocket and their perineum, and in general, comfort at rest.

ARTHRODESIS

6

In 1979, we reported on 71 shoulder arthrodeses done during the 25-year period up to 1974.7 The technique was largely intra-articular with incorporation of the acromion and fixation using screws. A spica cast was used in the postoperative period. Failure of fusion occurred in three. Forty-seven of sixty-six contacted (71%) had no or minimal pain. The pain was in the operative area in 10, the periscapular area in 5, and diffuse throughout the limb in 2. Three quarters of the patients could comfortably and with little difficulty eat, dress, attend to personal hygiene, sleep on the operated side, and carry a 5 to 7.5 kg weight. One half could comb their hair. Housewives, students, and farmers typically returned to their previous activities. Three quarters of office workers did the same. Only half of the laborers could do so. Contemporarily, fusions are typically done for paralysis of the deltoid and rotator cuff, secondary to a brachial plexus injury.6 , 41 , 42 , 53 Uncommonly, it is considered for other things including severely disorganizing trauma, arthritis with massive rotator cuff tearing and instability, instability uncorrectable by previous surgery, or as an adjunct to control of infection.10 , 11 , 23 There is always a question about the position of fusion. The most clear expression was by Rowe.39 He expressed the requirements for the extremity after shoulder arthrodesis would be that the hand should be able to reach the head, face, and midline of the body. The arm should be in a position of strength, and the shoulder should be comfortable with the arm at the side. To best accomplish these ends, he recommended fusion position of 20 degrees of abduction, 30 degrees of flexion, and 40 degrees of internal rotation relative to the trunk with the scapula in anatomic position. This

7

position question has been reconsidered by a number of more recent authors.16 , 20 , 29 , 34 , 35 , 38 , 43 , 53 Most have concurred with Rowe's general recommendations that abduction should be 20 to 30 degrees, flexion 20 to 30 degrees, and internal rotation 30 to 45 degrees. For internal fixation, screws have been carefully studied and three horizontal and three vertical screws are biomechanically quite stable.40 On occasion, it may seem useful to supplement screws with external fixation or use external fixation alone.17 , 52 However, most authors do recommend plate fixation often supplemented by transarticular screw fixation.12 , 34 , 36 , 42 , 46 After surgery, some surgeons consider the use of a splint. Most prefer a shoulder spica cast. Complications include pseudoarthrosis in approximately 10% of shoulders.6 , 40 , 46 An occasional infection will develop after surgery of this type.40 Many authors have reported humeral shaft fracture following successful healing.6 , 12 , 40 , 42 , 53 These have almost always healed with external support. Occasionally, healing in malposition occurs. Usually, this is rotational malposition combined with too much flexion or abduction. Osteotomy can be performed to correct this and has been done so successfully.14 , 16 P.370

References 1. Adams JE, Steinmann SP: Interposition arthroplasty using an acellular dermal matrix scaffold. Acta Orthop Belg 73(3):319-326, 2007.

8

2. Adams JE, Steinmann SP: Soft tissue interposition arthroplasty of the shoulder. J Shoulder Elbow Surg 16(5 Suppl):S254-S260, 2007. 3. Bhatia DN, van Rooyen KS, du Toit DF, de Beer JF: Arthroscopic technique of interposition arthroplasty of the glenohumeral joint. Arthroscopy 22(5):570e1-570e5, 2006. 4. Braman JP, Sprague M, Bishop J, et al: The outcome of resection shoulder arthroplasty for recalcitrant shoulder infections. J Shoulder Elbow Surg 15:549-553, 2006. 5. Burkhead WZ Jr, Krishnan SG, Lin KC: Biologic resurfacing of the arthritic glenohumeral joint: Historical review and current applications. J Shoulder Elbow Surg 16(5 Suppl):S248-S253, 2007. 6. Chammas M, Meyer zu Reckendorf G, Allieu Y: Arthrodesis of the shoulder for post-traumatic palsy of the brachial plexus. Analysis of a series of 18 cases. Revue de Chirurgie Orthopedique et Reparatrice de l Appareil Moteur 82(5):386395, 1996. 7. Cofield RH, Briggs BT: Glenonhumeral arthrodesis: Operative and long-term functional results. J Bone Joint Surg 61:668, 1979. 8. Cofield RH: Shoulder arthrodesis and resection arthroplasty. AAOS Instructional Course Lectures. CV Mosby Co, St. Louis, E.S. Stauffer, Vol. 34, 1985, pp 268-277. 9. Copeland SA, Lettin AWF, Scales JT: The Stanmore total shoudler replacement, a clinical review. J Bone Joint Surg 60:144, 1978 (Abstract). 10. David A, Makowski S, Muhr G: Post-traumatic shoulder arthrodeses - indications, technique, results. Unfallchirurg 98(11):566-569, 1995.

9

11. Diaz JA, Cohen SB, Warren RF, et al: Arthrodesis as a salvage procedure for recurrent instability of the shoulder. J Shoulder Elbow Surg 12(3):237-241, 2003. 12. Dimmen S, Madsen JE: Long-term outcome of shoulder arthrodesis performed with plate fixation: 18 patients examined after 3 to 15 years. Acta Orthop 78(6):827-833, 2007. 13. Fink B, Sallen V, Guderian H, et al: Resection interposition arthroplasty of the shoulder affected by inflammatory arthritis. J Shoulder Elbow Surg 10(4):365-371, 2001. 14. Groh GI, Williams GR, Jarman RN, Rockwood CA Jr: Treatment of complications of shoulder arthrodesis. J Bone Joint Surg 79A(6):881-887, 1997. 15. Ho JY, Miller SL: Allografts in the treatment of athletic injuries of the shoulder. Sports Med Arthroscopy 15(3):149157, 2007. 16. Huber HM, Gschwend N. Shoulder arthrodesis. Possible causes of functionally poor results. Zeitschrift fur Orthopadie und Ihre Grenzgebiete 131(1):18-21, 1993. 17. Johnson CA, Healy WL, Brooker AF Jr, Krackow KA: External fixation shoulder arthrodesis. Clin Orthop 211:219223, 1986. 18. Jones L: Reconstructive operation for non-reducible fractures of the head of the humerus. Ann Surg 97:217, 1933. 19. Jones L: The shoulder joint - observations on the anatomy and physiology: With an analysis of a reconstructive operation following extensive injury. Surg Gynecol Obstet 75:433, 1942. 20. Jonsson E, Brattstrom M, Lidgren L: Evaluation of the rheumatoid shoulder function after hemiarthroplasty and arthrodesis. Scand J Rheum 17(1):17-26, 1988.

10

21. Knight RA, Mayne JA: Comminuted fractures and fracturedislocations involving the articular surface of the humeral head. J Bone Joint Surg 39:1343, 1957. 22. Krishnan SG, Nowinski RJ, Harrison D, Burkhead WZ: Humeral hemiarthroplasty with biologic resurfacing of the glenoid for glenohumeral arthritis. Two to fifteen-year outcomes. J Bone Joint Surg Am 89(4):727-734, 2007. 23. Lacombe F, Coulet B, Chammas M, Allieu Y: L'arthrodese scapulo-humerale dans l'epaule non neurologique: A propos de 8 ans. [Scapulohumeral arthrodesis for non-neurological shoulder: A study of 8 cases]. Revue de Chirurgie Orthop et Reparatrice de l Appareil Moteur 91(6):515-522, 2005. 24. Larson AN, Morrey BF: Interposition arthroplasty with an Achilles tendon allograft as a salvage procedure for the elbow. J Bone Joint Surg Am 90(12):2714-2723, 2008. 25. Lunn JV, Castellanos-Rosas J, Walch G: Arthroscopic synovectomy, removal of loose bodies and selective biceps tenodesis for synovial chondromatosis of the shoulder. J Bone Joint Surg Br 89(10):1329-1335, 2007. 26. Mahieu X, Chaouat G, Blin JL, et al: Arthroscopic treatment of pigmented villonodular synovitis of the shoulder. Arthroscopy 17(1):81-87, 2001. 27. Mason JM: The treatment of dislocation of the shoulder joint complicated by fracture of the upper extremity of the humerus. Ann Surg 47:672, 1908. 28. Mills KLG: Severe injuries of the upper end of the humerus. Injury 6:13, 1974. 29. Nagy L, Koch PP, Gerber C: Functional analysis of shoulder arthrodesis. J Shoulder Elbow Surg 13(4):386-395, 2004.

11

30. Neer CS, Brown TH Jr, McLaughlin HL: Fracture of the neck of the humerus with dislocation of the head fragment. Am J Surg 85:252, 1953. 31. Pahle JA, Kvarnes L: Shoulder synovectomy. Ann Chir Gynaecol Suppl 198:37, 1985. 32. Pahle JA: The shoulder joint in rheumatoid arthritis: Synovectomy. Reconstr Surg Traumatol 18:33, 1981. 33. Raiss P, Aldinger PR, Kasten P, et al: Total shoulder replacement in young and middle-aged patients with glenohumeral osteoarthritis. J Bone Joint Surg Br 90(6):764769, 2008. 34. Reichelt A: Arthrodesis of the shoulder joint. Orthopade 25(2):104-111, 1996. 35. Richards RR, Sherman RM, Hudson AR, Waddell JP: Shoulder arthrodesis using a pelvic-reconstruction plate. A report of eleven cases. J Bone Joint Surg 70A(3):416-421, 1988. 36. Richards RR, Beaton D, Hudson AR: Shoulder arthrodesis with plate fixation. Functional outcome analysis. J Shoulder Surg 2:225, 1993. 37. Rispoli DM, Sperling JW, Athwal GS, et al: Pain relief and functional results after resection arthroplasty of the shoulder. J Bone Joint Surg 89B:1184-1187, 2007. 38. Rose CR: Re-evaluation of the position of the arm in arthrodesis of the shoulder in the adult. J Bone Joint Surg 56A:913-922, 1974. 39. Rowe CW: Re-evaluation of the position of the arm in arthrodesis of the shoulder in the adult. J Bone Joint Surg 56A:913, 1974. 40. Ruhmann O, Bohnsack M, Schmolke S, et al: Shoulder arthrodesis with plate fixation. Special features in cases of

12

resection and defects. Zeitschrift fur Orthopadie und Ihre Grenzgebiete 140(6):662-671, 2002. 41. Ruhmann O, Kirsch L, Buch S, et al: Primary stability of the shoulder arthrodesis using cannulated cancellous screws. J Shoulder Elbow Surg 14(1):51-59, 2005. 42. Ruhmann O, Schmolke S, Bohnsack M, et al: Shoulder arthrodesis: Indications, technique, results and complications. J Shoulder Elbow Surg 14(1):38-50, 2005. 43. Safran O, Iannotti JP: Arthrodesis of the shoulder. JAAOS 14(3):145-153, 2006. 44. Smith AM, Sperling JW, O'Driscoll SW, Cofield RH: Arthroscopic shoulder synovectomy in patients with rheumatoid arthritis. Arthroscopy 22(1):50-56, 2006. 45. Sperling JW, Steinmann SP, Cordasco FA, et al: Shoulder arthritis in the young adult: Arthroscopy to arthroplasty. Instr Course Lect 55:67-74, 2006. 46. Stark DM, Bennett JB, Tullos HS: Rigid internal fixation for shoulder arthrodesis. Orthopedics 14(8):849-855, 1991. 47. Steindler A: Orthopedic Operations: Indications, Technique, and End Results. Springfield, Charles C. Thomas, 1940, p. 302. 48. Svend-Hansen H: Displaced proximal humeral fractures. A review of 49 patients. Acta Orthop Scan 56:359, 1974. 49. Urbach D, McGuigan FX, John M, et al: Long-term results after arthroscopic treatment of synovial chondromatosis of the shoulder. Arthroscopy 24(3):318-323, 2008. 50. Vainio K: Synovectomy for the treatment of progressive chronic polyarthritis [German]. Munch Med Wochenschr 26:111, 1973. 51. Van Heest AE, Kallemeier P: Thumb carpal metacarpal arthritis. J Am Acad Orthop Surg 16(3):140-151, 2008.

13

52. Vancabeke M, Baillon B, Remy P, et al: Shoulder arthrodesis using combined internal and external fixation. A review of 9 cases. Acta Orthop Belgica 73(6):696-699, 2007. 53. Wong ELW, Kwan MK, Loh WYC, Ahmad TS. Shoulder arthrodesis in brachial plexus injuries: A review of six cases. Med J Malaysia 60(Suppl C): 72-77, 2005.

14