15

Surgery of the rheumatoid shoulder

S. C O P E L A N D

Approximately 60% of patients with rheumatoid arthritis have clinical symptoms of shoulder involvement (see Chapter 11). However, although the shoulder is often affected, it is only unusually the site of severe destruction and this almost exclusively occurs when there is severe destruction of other joints. Furthermore, in nearly all the patients with major shoulder involvement, destruction appears much later than in the other joints. This may be part of the explanation of why most surgeons have been hesitant with regard to operative treatment of the rheumatoid shoulder in the past.

It has been noted by many that function in the upper limb can remain remarkably good, even in the face of a totally destroyed shoulder joint, as eventually the joint can become a functional arthrodesis and what movement there is takes place at the scapulothoracic joint. The scapulo- thoracic joint allows reasonable flexion, extension, abduction and adduction but only minimal rotation, resulting in the main functional disability.

The majority of those patients coming to surgery for the shoulder have other severely destroyed joints in the upper limb and therefore some priority of treatment must be considered. Traditionally, the shoulder has taken rather low surgical priority because of the 'fallback' mechanism of the scapulothoracic joint. However, in end-stage rheumatoid disease, when joint replacement is being considered, pain relief is obviously the first consideration. If there is a choice between shoulder and elbow replacement then it is best to replace the shoulder first. If an elbow replacement is done in the presence of a stiff shoulder with little rotation, greater strain will be placed on the elbow joint to accommodate some degree of rotation and this can precipitate loosening. Attempts have been made to correlate clinical signs and symptoms with radiographic findings (Crossan and Valance, 1980); however, little correlation can be found until quite marked end-stage destruction. It cannot be assumed that all pain 'emanating from the shoulder' is arising from the glenohumeral joint, even in the presence of quite marked radiographic destruction. Kelly (1988) has shown, by local anaesthetic injection studies, that 60% of patients with Larsen grade IV and V changes (Larsen et al, 1977) can have their pain completely abolished by injections either into the acromioclavicular joint or the subacromial bursa. One millilitre 1% lignocaine was injected sequentially into the subacromial bursa, the acromioclavicular joint, the long head of biceps, and finally the

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glenohumeral joint, until the pain was totally abolished. In approximately 30%, the pain was totally relieved by acromioclavicular joint injection alone; this technique is highly recommended to help elucidate the actual site of pain and hence provide a rational mode of treatment. Even in the face of quite marked destruction, a simple excision of the acromioclavicular joint can abolish most of the pain and hence enormously increase the function of an otherwise very limited shoulder.

SOFT TISSUE SURGERY

Nerve entrapment syndromes

The occurrence of median nerve compression at the wrist has a well-known association with rheumatoid arthritis; however, it is less well recognized that other nerve compression syndromes can occur around the shoulder. These are much less common but can give rise to quite painful and disabling symptoms which, if recognized, can be reasonably easily treated.

Suprascapular nerve entrapment

The suprascapular nerve arises from the upper trunk of the brachial plexus at the confluence of C5 and C6 and derives most of its fibres from C5. It is the only branch of the upper trunk and is directed posteriorly and laterally beneath the trapezius to the upper border of the scapula, medial to the base of the coracoid process, where it passes beneath the superior transverse scapular ligament to pass through the suprascapular notch; the supra- scapular artery which accompanies the nerve passes above the ligament. The nerve then passes to the deep surface of the supraspinatus, which it supplies, and around the lateral border of the spine of the scapula to supply the infraspinatus.

Because of the anatomical confinement and the relative immobility of the suprascapular nerve within the notch, there is a predisposition to compres- sion and irritation or traction lesions of the nerve with either forced depres- sion of the shoulder or repetitive movements (Clein, 1975). This can also occur in rheumatoid disease, secondary to local swelling (Varstamaki, 1988). Clinically, these patients present with pain over the superior border of the scapula and try to demonstrate it by digging their finger into the substance of trapezius. Night pain can also be a feature. There is marked weakness of lateral rotation and diagnosis must be confirmed by electro- myographic studies.

This particular syndrome has been mistaken for rotator cuff pathology (Drez, 1976). If the syndrome is suspected, local anaesthetic can be injected into the region of the suprascapula notch. This abolishes the pain, but local steroid injection has not been found to give any lasting relief. Once the diagnosis has been confirmed, surgical release is indicated by division of the suprascapular ligament. If the diagnosis has been confirmed by electro- myographic studies then the results of surgery are reliable.

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Axillary nerve entrapment

Entrapment of the axillary nerve in the quadrilateral space can cause chronic shoulder pain. The axillary nerve is surrounded by the teres major and minor and triceps muscles and by the humerus in the quadrilateral space. The patient typically presents with a dull ache over the posterior area of the axilla. In advanced cases, wasting of the deltoid can be observed. If tender- ness is found over the quadrilateral space, diagnosis must again be con- firmed by electromyographic studies and pain can be relieved by external neurolysis of the axillary nerve. This is a rare condition (Varstamaki, 1988).

Shoulder synovectomy

Synovectomy is really a misnomer as most shoulder operations of this sort are subacromial bursectomies with concomitant partial synovectomy. It is difficult to diagnose lone shoulder synovitis; swelling only becomes visible when the joint involved starts communicating with the surrounding bursae via the rotator cuff. This is often associated with rupture of the long head of the biceps.

Results of early synovectomy of the shoulder have been said to be good, but the operation is rarely done. Pain and swelling are reduced, but mobility following surgery depends largely on the absence of a rotator cuff tear (Pahle, 1983). Synovectomy of the shoulder follows a similar pattern to that of synovectomy at other joints, in that the earlier it is done, the better the results; long-term benefit can be expected, with some loss of progression of radiographic signs reported over 10 years (Pahle, 1981).

The indications for early synovectomy require early diagnosis of synovitis. Unfortunately, pain in the shoulder is not a reliable criterion. To await the onset of visible swelling with bursitis means losing precious time. Gallium and technetium scanning have been found, by correlation of arthroscopy findings, to be reliable methods of diagnosing early synovitis. Surgical synovectomy should only be attempted in patients without severe radio- graphic damage (Larsen's stage I or II).

Rotator cuff impingement

Rotator cuff impingement is a potent cause of pain in the rheumatoid shoulder. As mentioned previously, if there is obvious swelling in the subacromial bursa, it is usually associated with a complete rotator cuff rupture. However, in the absence of swelling but in the presence of a painful arc of abduction, with local anterior rotator cuff tenderness and pain on forced internal rotation in abduction, impingement must be suspected. If this pain is abolished by a local anaesthetic and fails to resolve with local steroid injections, then decompression by anterior acromioplasty and excision of the coracoacromial ligament is indicated. Doubt has been expressed about doing this operation in rheumatoid conditions as this could theoretically increase the chance of anterosuperior subluxation of the humeral head. However, this fear does not seem to be borne out in practice (Kelly, 1988).

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Shoulder arthroscopy

Arthroscopy of the shoulder is an investigative technique in the manage- ment of shoulder conditions which has been established as a safe and reasonable procedure for some years (Cofield, 1983).

Arthroscopic assessment of the rheumatoid shoulder may be useful for staging but arthroscopic surgery itself has not been shown to be as useful as in the knee. D6bridement of rotator cuff tears has been described (Ogilvie- Harris and Wiley, 1986), but the results were not good. Only patients with rotator cuff tendonitis rather than an actual tear did well. The main reason why those with tears did badly was that the intra-articular ddbridement did not relieve the extra-articular impingement of the rotator cuff with which they are associated (Earnshaw et al, 1982). Early results of arthroscopic resection of the coracoacromial ligament with partial anterior acromion- ectomy is being more widely done but no long-term results are yet available (Ellman, 1987).

Arthroscopic synovectomy

Ogilvie-Harris and Wiley (1986) described 11 patients with rheumatoid arthritis of the shoulder who underwent arthroscopic synovectomy. The patients did not have radiographic evidence of gross degenerative change. They did, however, have persistent weakness and swelling of the shoulder that had not responded to conservative management. An arthroscopic synovectomy using power instruments was performed on these patients. This was often technically difficult because of bleeding; a double irrigation system had to be used. Postoperatively, the patients were mobilized and active physiotherapy instituted immediately. Of the 11 patients, nine had significant improvement with less pain and increased movement. However, the follow-up was short. There have been other reports of arthroscopic synovectomy of the shoulder but no long-term results are yet available. This does seem a promising technique, although technically difficult.

OSTEOTOMY AND ARTHROPLASTY

Double osteotomy

Double osteotomy, as originally described by Benjamin (1974), has been suggested as an alternative to arthroplasty in less advanced cases of rheumatoid disease of the shoulder. The results are found to be better in osteoarthritis than in the rheumatoid arthritis patient, but could perhaps be best applied to the juvenile polyarthritic suffering from secondary osteoarthritis pain but with little disease activity.

Glenoidectomy

Removal of the glenoid was described by Wainwright (1974) and by Gariepy

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(1976). Both authors claim good relief of pain with little functional inter- ference; however, personal experience has been that good relief of pain is only obtainable at the expense of both movement and power. This operation is rarely carried out nowadays.

Arthroplasty In 1980, Varian presented his early experience of 32 shoulder arthroplasties in 29 patients using a silastic cup as an interposition. Pain relief was reported in all but two patients. He noted an overall improvement in function of the shoulder, but no gain in movement was noted apart from increased scapulo- thoracic movement, which may have been due to diminution of pain. Complications noted were four torn prostheses and five dislocations (Figure 1). This did not invariably mean that the prosthesis had to be removed, as some patients remained pain free. In 1986, Spencer and Scurving reported on the use of the Varian silastic interpositional arthroplasty in 12 patients with rheumatoid arthritis but there was a high incidence of dislocation; fragmentation leading to early failure of the device in seven of the patients. They felt that although the incidence of failure was high, it still had a place in the painful rheumatoid shoulder without severe humeral head destruction. They also pointed out that an extensive synovectomy accompanied the insertion of the cup, and that much of the early pain relief could well be attributed to that procedure. In other words, the silastic interposition may be an irrelevance.

Figure 1. Varian silastic interposition arthroplasty. Fragmentation at revision surgery to a total replacement.

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Replacement hemiarthroplasty

Proximal humeral hemiarthroplasty was originally used by Neer for replace- ment of the humeral head in cases of four-part fracture. Because of the encouraging results when used in fracture, its indication was extended for use in degenerative arthritis. The glenoid component of the Neer prosthesis came later; hence, the early results relate only to hemiarthroplasty (Neer, 1971). However, because of technical difficulties with replacing the glenoid in a grossly eroded shoulder, and problems with loosening of the glenoid component in the severe rheumatoid shoulder, there was a general trend back to hemiarthroplasty. From several subsequent detailed studies comparing hemiarthroplasty and total joint replacement, it now seems that the results are better when both components (glenoid and humerus) are replaced (Cofield, 1984; Gschwend and Ivosevic-Radovanovic, 1988).

Total shoulder replacement arthroplasty

A dilemma occurs in the rheumatoid shoulder as to when total joint replacement is indicated. The surgical results of shoulder replacement are much better if done early in the disease process, before gross destruction of the bony geometry and rupture of the rotator cuff occur. However, a grossly destroyed rheumatoid shoulder can often be compatible with reasonable function and little pain. It is also known that during the disease process the shoulder joint may become extremely painful during the early stages but, as bone destruction and limitation of movement progress, the shoulder can become reasonably pain free again. By the time this stage is reached, the shoulder is functioning almost as an arthrodesis, hence putting a greater strain on other joints in the upper limb. In view of the better results reported for non-constrained prostheses, the trend is now towards replacement of the joint during the earlier stages, in order to maintain shoulder function and mobility and to improve the function of the whole upper limb.

Earlier joint replacements were constrained with a fixed fulcrum. This was to prevent the upward subluxation of the humeral head when the disease process had completely destroyed the rotator cuff. However, taking an average of all the large published series of total shoulder replacement in the rheumatoid patient, the rotator cuff was noted to be destroyed in only approximately 20%. The constrained type of shoulder joints have varied enormously in their engineering design; as with constrained joints at other anatomical sites, the main problem is that of component loosening at the bone-cement interface. In the case of the shoulder joint, it is nearly always the glenoid component that fails. The bone stock available for fixation of an implant is inadequate for the forces which can be transmitted through the upper limb. It must be borne in mind that, in the severely disabled rheumatoid, the upper limb is often a weight-bearing joint, in that the patient may be using crutches or sticks. The end-stage rheumatoid patient coming to shoulder replacement may have gross loss of bone stock and even less material for fixation of the glenoid component.

The Stanmore total shoulder replacement was the first widely used, totally

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constrained shoulder replacement (Copeland et al, 1978). Unfortunately, approximately one-third of these underwent glenoid loosening. Most of the totally constrained designs have now been abandoned but the Kessel total shoulder is still used in some centres for completely rotator cuff deficient shoulders (Kessel and Bayley, 1982). This shoulder replacement uses the reversed head design which, it was felt, provided a better range of abduction and circumduction combined with stability; the socket was placed on the humeral side and the ball on the glenoid side.

Because of the generally poor results gained in the use of the constrained types of prostheses, the non-constrained design of Neer has been gaining in popularity. Neer has reported a large series of results for use of the prosthesis in both osteoarthritis and rheumatoid arthritis (Neer et al, 1982). He separated out a 'limited goals' group in which the joint was severely destroyed by rheumatoid arthritis. In general, the results of the use of this prosthesis, when the bony geometry is not grossly destroyed and the rotator cuff is intact, are very reliable and rewarding. However, the results when the rotator cuff is destroyed are not so good in terms of movement, although still reliable in terms of pain relief and functional ability. Neer has always stressed the importance of soft tissue reconstruction around the non- constrained shoulder and the importance of a prolonged and adequate physiotherapy regimen following replacement. He starts very early in the postoperative phase, with passive movements, followed by passive assisted and then strengthening and stretching exercises. This programme should continue for a year after replacement and gains can be expected throughout this first year. The Neer prosthesis, which is essentially a surface replacement, can be expected to give excellent results when the main problem is destruction of the glenohumeral interface but with good preservation of soft tissues. However, in the face of severe rheumatoid disease, when the soft tissues are destroyed, it cannot be expected to produce a normal range of movement. It certainly appears to be important to gain a good range of passive external rotation at the time of operation. If this is not done, it is unlikely to be achieved at a later stage. It is also essential to try to lateralize the centre of rotation to the anatomical position (Boni, 1988) (Figure 2). This can often prove difficult in the rheumatoid patient, when gross glenoid erosion has medialized the centre of rotation, with consequent soft tissue shortening and fibrosis, but with the use of a non- constrained design the earlier problems of glenoid loosening seem to have been greatly reduced. However, radiolucent lines around the glenoid component have been seen in 31% of Neer cemented glenoid prostheses, although nearly all these patients exhibited the same radiolucent lines in their initial postoperative radiographs and there was no tendency for enlargement or widening of the lines.

As for the future, many forms of cementless-type surface replacement designs are now being developed (Figures 3 and 4), but as yet no large series or long-term follow-up is available. '

The indication for total replacement remains intolerable pain. Predictions concerning range of movement must remain guarded, depending on loss of bony architecture and soft tissue destruction. With little bone loss an almost

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Figure 2. Left, resolution of deltoid forces about the head of humerus, the greater tuberosity acting as fulcrum. Right, Erosion of the joint results in medialization, decrease of tension in the deltoid, loss of the tuberosity fulcrum and superiorly directed resolution of forces, causing upward subluxation, even in the presence of an intact rotator cuff.

Figure 3. Moderate erosion of the glenoid and humeral head.

SURGERY OF THE RHEUMATOID SHOULDER 689

Figure 4. Copeland cementless surface replacement has lateralized the centre of rotation and restored mechanical advantage.

normal range of movements can be achieved, but with gross end-stage rheumatoid shoulder only a limited functional range can be promised. However , with loss of pain, increase of function is disproportionate to the increased range of movement. The greatest disability the patient finds with a stiff shoulder, from whatever cause, is loss of rotation. A shoulder replacement, even in the most grossly destroyed shoulder, can reliably provide a good range of internal and external rotation at waist height, coupled with reliable increase in extension, so that most activities of daily living can be facilitated. The success or failure of shoulder surgery is often judged on the ability to abduct. In most activities this is a useless movement and rarely required, the most useful range being extension, external rotation and internal rotation. As long as the patient can easily flex to shoulder height

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and rotate painlessly, most activities can be accomplished. This is the least that can be predictably expected of shoulder replacement, which often results in a great deal more.

At the present time, shoulder replacement is a reliable procedure that can be recommended to relieve pain and give an adequate functional range of m o v e m e n t , even in the severe rheumatoid patient. However , it should be considered at an earlier stage, before gross soft tissue and bony destruction, if maximal benefits are to be achieved.

REFERENCES

Benjamin A (1974) Double osteotomy of the shoulder. Scandinavian Journal of Rheumatology 3: 65.

Boni A (1988) The lever arm in gleno-humeral abduction after hemi-arthroplasty. Journal of Bone and Joint Surgery 70B: 561.

Clein LJ (1975) Suprascapular entrapment neuropathy. Journal of Neurosurgery 43: 337. Cofield RH (1983) Arthroscopy of the shoulder. Mayo Clinic Proceedings 58: 501-508. Cofield RH (1984) Total shoulder arthroplasty, associated disease of the rotator cuff and

complications. In Bateman & Welsh (eds) Surgery of the Shoulder, pp 229-239. St Louis: Mosby.

Copeland SA, Lettin AWF & Scales JT (1978) Stanmore total shoulder replacement. Journal of Bone and Joint Surgery 60(B): 144.

Crossan & Valance (1980) Clinical and radiological features of the shoulder joint in rheumatoid arthritis. Journal of Bone and Joint Surgery 54(A): 141-150.

Drez D (1976) Suprascapula neuropathy and the differential diagnosis of rotator cuff injuries. American Journal of Sports Medicine 4: 43.

Earnshaw P, Des Jardins D, Sarkar K & Uhthoff HK (1982) Rotator cuff tear in the role of surgery. Canadian Journal of Surgery 25: 60-63.

Ellman H (1987) Arthroscopic sub-acromial decompression analysis: 1-3 year results. Arthroscopy 3: 173-181.

Gariepy R (1976) Glenoidectomy in the repair of the rheumatoid shoulder. 6th Combined Meeting of the Orthopaedic Association of the English Speaking World, London.

Gschwend N & Ivosevic-Radovanovic (1988) Is the glenoid component necessary for rheumatoid patients? Proceedings of the 2nd Congress of the European Society for Surgery of the Shoulder and Elbow, Berne.

Kelly IG (1988) Proceedings of the 2nd Congress of European Society for Surgery of the Shoulder and Elbow, Berne.

Kessel L & Bayley I (1982) Prosthetic replacement of the shoulder joint. Journal of Royal Society of Medicine 72: 748-752.

Larsen A, Dahle K & Eek M (1977) Radiographic evaluation of rheumatoid arthritis and related conditions by standard reference films. Acta Radiologica: Diagnosis 18: 92.

Neer CS (1971) The rheumatoid shoulder. In Cruess RL & Mitchell N (eds) Surgery of Rheumatoid Arthritis, pp 117-125. Philadelphia: Lippincott.

Neer CS, Watson KC & Stanton FJ (1982) Recent experience in total shoulder replacement. Journal of Bone and Joint Surgery 64A: 319-337.

Ogilvie-Harris DJ & Wiley AM (1986) Arthroscopic surgery of the shoulder. Journal of Bone and Joint Surgery 68B(2): 201-207.

Pahle JA (1981) The shoulder joint in rheumatoid arthritis; synovectomy, p 33. Reconstructive Surgery and Traumatology vol. 18. Basel: Karger.

Pahle JA (1983) Late results in synovectomy of the shoulder. Proceedings of the Congress of the European Society for Surgery of the Shoulder and Elbow, Moscow.

Spencer R & Scurving AP (1986) Silastic interposition arthroplasty of the shoulder. Journal of Bone and Joint Surgery 68B: 375-377.

Varian JPW (1980) Interpositional silastic cup arthroplasty of the shoulder. Journal of Bone and Joint Surgery 62B: 116-117.

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Varstamaki M (1988) Proceedings of the 2nd Congress of the European Society for Surgery of the Shoulder and Elbow, Berne.

Wainwright D (1974) Glenoidectomy--method of treating the painful shoulder in severe rheumatoid arthritis. Annals of the Rheumatic Diseases 33(1): 110.