Outcomes of instability after reverse shoulder arthroplasty: reoperation and persistent instability are common

Hypothesis: Although risk factors for instability after reverse shoulder arthroplasty (RSA) have been extensively studied, the outcomes of patients who experience instability are unknown. The purpose of this study was to evaluate functional outcomes in patients with instability after RSA.

Methods: We retrospectively identified patients with instability after RSA with a minimum of 2 years' follow-up from an institutional database. Baseline data were recorded, and all patients we contacted to obtain clinical outcome scores. Patients who required revision surgery and those treated successfully with closed reduction were compared.

Results: Fifty patients were included. Of these patients, 40 (80%) required revision surgery whereas 10 (20%) were treated successfully with closed reduction. At an average follow-up of 63.7 months (range, 24-123 months), outcome scores did not differ between groups. Patients who required revision surgery were more likely to have undergone previous shoulder surgery, prior to their index arthroplasty (P = .031). Seventeen patients (42.5%) reported recurrent instability following revision surgery, and 14 (35.0%) required additional revision surgery. Ultimately, stability was never achieved in 7 of 50 patients (14%) after their index instability event.

Conclusion: Although instability after RSA can commonly be corrected with reasonable functional results, multiple procedures may be needed and some patients may experience persistent instability.