A comparison of reverse shoulder arthroplasty and glenohumeral arthrodesis for end-stage shoulder instability.

Hypothesis: End-stage multidirectional recurrent shoulder instability (RSI) that is unresponsive to nonoperative treatment is a puzzling pathology, with no consensus on standard of care. The purpose is to report and compare outcomes of glenohumeral arthrodesis (GHA) and reverse total shoulder arthroplasty (rTSA). We hypothesized that both treatment options would be acceptable, but rTSA patients would have better function and higher patient satisfaction. Methods: Patients who underwent primary GHA or rTSA for isolated RSI by a single surgeon were included. Failure was defined as a conversion surgery or major component exchange. Patient-reported outcome measures (American Shoulder and Elbow Surgeons, Single Assessment Numerical Evaluation, Quick Disabilities of the Arm, Shoulder and Hand, 12-item Short Form) were assessed preoperatively and postoperatively. Persistent instability and patient satisfaction were reported. Results: Thirteen shoulders in 11 patients with end-stage RSI underwent either GHA (n = 8) or rTSA (n = 5) with a mean age was 29.7 ± 11.8 years. Ehlers-Danlos syndrome was present in 5 patients. Follow-up rate was 93% (12/13). One GHA patient required conversion to rTSA. One GHA patient underwent hardware removal and a varus-producing osteotomy for scapular pain. No persistent instability was reported. No significant differences were found in demographics or preoperative patient-reported outcomes. American Shoulder and Elbow Surgeons (GHA: 64.4 ± 15.4; rTSA: 89.6 ± 12.6, Conclusion: rTSA and GHA are viable options in treating end-stage RSI. rTSA resulted in better function and lower revision surgery rates, suggesting rTSA provides better shoulder mobility while maintaining stability.