Paper #29 - Anatomic shoulder arthroplasty with plication of the posterior capsule compared to reverse shoulder arthroplasty for osteoarthritis with B2 glenoid: a matched cohort study

Abstract

Introduction: A subset of patients with primary glenohumeral osteoarthritis presents with posterior subluxation and eccentric posterior glenoid bone loss (B2 glenoid). Posterior capsular plication is sometimes required to balance the shoulder when performing an anatomic shoulder arthroplasty. More recently, reverse arthroplasty has been advocated for glenohumeral osteoarthritis with severe posterior subluxation. To date, no study has compared these two alternatives for shoulders with marked posterior subluxation. The purpose of this study was to compare the clinical and radiographic outcomes of a matched cohort of shoulders with B2 glenoids treated with either anatomic total shoulder arthroplasty (TSA) with plication of the posterior capsule or a reverse shoulder arthroplasty (RSA). Methods: All shoulder arthroplasties performed for glenohumeral osteoarthritis at a single institution between 1975 and 2013 were reviewed to identify two matched cohorts. Group 1 included 15 TSA in shoulders with B2 glenoids that required posterior capsule plication. Group 2 included 16 RSA in shoulders with B2 glenoids. Both groups were similar in terms of age (70 ± 7.5 years vs 72 ± 5.4 years), BMI (31 ± 3.9 vs 32. ± 1.6) and follow-up (42.8 ± 18.4 vs 35.1 ± 14.2). The records of these patients were reviewed to determine pain, range of motion (ROM), strength, Neer rating scale, simple shoulder test, ASES score, satisfaction, complications, reoperations, radiolucency lines and implant loosening. Radiographic information was obtained preoperatively, in the immediate postoperative period and at last radiographic follow-up. Results: With the numbers available, at most recent follow-up, there were no significant differences in pain (P = .2), forward flexion (P = .7), external rotation (P = .5), internal rotation (P = .4), forward flexion strength (P = .3), abduction strength (P = .8), external rotation strength (P = .5), internal rotation strength (P = .8), ASES scores (P = .08), or satisfaction (P = .3). The simple shoulder test score was significantly better in TSA compared to RSA (10.6 vs 8.5, P = .01). There were no reoperations in either group. Radiographically, in the TSA group there were 2 shoulders with glenoid loosening, 2 shoulders with progressive cuff insufficiency, and 1 shoulder with recurrent posterior subluxation and 1 additional shoulder with recurrent posterior subluxation and glenoid loosening. In the RSA, there were no cases of loosening or notching. Conclusions: The overall clinical outcome of anatomic TSA in patients with a B2 glenoid and subluxation requiring posterior capsular plication seems to be similar to the outcome of RSA in patients with a B2 glenoid. However, the rate of radiographic glenoid loosening, cuff insufficiency, and recurrent posterior subluxation after TSA remains of concern.