INTERMEDIARY ARTHROPLASTY FOR THE RHEUMATOID SHOULDER WITH IRREPARABLE ROTATOR CUFF TEARS: OUTCOME AT MORE THAN FIVE YEARS

Abstract

Purpose of the study: Fragile bone and weak soft tissues can create a serious challenge for arthroplasty of the rheumatoid arthritis shoulder. Patients seen late after rotator cuff tears become irreparable may also present a stiff shoulder, further complicating the procedure.

Material and methods: The purpose of this study was to assess outcome at more than five years in a prospective series of 12 patients with rheumatoid arthritis of the shoulder with an irreparable rotator cuff tear treated with a hemiarthroplasty with a mobile cup. The radiological and clinical results were compared with those obtained in a control series of ten bipolar humeral prostheses implanted for centered or excentered degenerative disease with irreparable cuff tears.

Results: The mean preoperative Constant score was 16.9 points: pain 2.5, activity 4.2, active mobility 9.5, strength 0.7. Active ROM was 63.8° for anterior elevation, 45° for abduction, and 12° for external rotation. At last follow-up, the mean postoperative Constant score was 39.4 points: pain 10.7, activity 10.8, active mobility 13.8, strength 4.1. Mean active anterior elevation was 83.7°, abduction 70.4°, and external rotation 29.1°. Outcome was not significantly different from the control group with degenerative joint disease (p< 0.05).

Discussion: The overall Constant score, especially the pain score, was significantly improved (p< 0.05). Improvement in joint motion was modest but comparable with other series in the literature and even better than with conventional hemiarthroplasty for the same indication. There were few complications, mainly superior subluxation favored by the preoperative infra-scapularis or infraspinatus tears. Glenoid wear was significant despite the dual mobility concept. There were no cases of loosening.

Conclusion: These results show that hemiarthroplasty with a mobile cut provides acceptable mid-term results for the advanced-stage rheumatoid shoulder with an irreparable rotator cuff tear. Results in this series were comparable with that in the control group of patients with degenerative joint disease. Consequently, the status of the rotator cuff appears to be more important that the inflammatory or degenerative etiology. Certain cuff tears involving the infrascapularis raise the risk of superoanterior instability and could be a limitation for this method. A more constrained prosthesis might be advisable.