Reverse shoulder arthroplasty in the treatment of glenohumeral instability

Abstract

Glenohumeral instability is a rare indication for primary reverse total shoulder arthroplasty (RTSA), accounting for fewer than 1% of the indications in the literature. The aim of this study was to analyze the clinical and radiographic outcomes of RTSA for recurrent instability after failed operative repair or instability associated with major bone loss in elderly patients. A retrospective matched case-control study was performed. We compared 11 shoulders treated with RTSA for instability (cases) with 22 matched shoulders treated with RTSA for rotator cuff insufficiency (controls). Clinical and radiographic outcomes were compared. The median follow-up period was 74 months (interquartile range [IQR], 18 months; range, 22-171 months) in cases and 70 months (IQR, 13 months; range, 23-172 months) in controls. The median age was 74 years (IQR, 18 years) in the case group and 70 years (IQR, 13 years) in the control group. No significant differences were found between the 2 groups in satisfaction scores, preoperative and postoperative absolute and relative Constant scores, and complication rates. Active range of motion tended to be superior in the controls for mean flexion (130° vs. 110°, P = .15), abduction (143° vs. 100°, P = .16), and external rotation (28° vs. 20°, P = .86) without the differences reaching statistical significance, possibly because of the small sample size. Postoperative dislocation was not recorded in cases or controls, but subjective insecurity regarding stability was reported once in each group. RTSA seems to represent a valuable treatment option for glenohumeral instability in an elderly population with large bone loss or as a salvage procedure after failed operativeglenohumeral stabilization. Postoperative instability was not observed in the case and control groups.