Reverse shoulder arthroplasty in patients younger than 55 years: 2- to 12-year follow-up.

Background: This study reports the outcomes of reverse shoulder arthroplasty (RSA) in patients younger than 55 years with midterm to long-term follow-up.

Methods: Sixty-seven patients (average age, 47.9 years; range, 21-54 years) were identified who underwent RSA with an average 62.3 months of follow-up (24-144 months). There were 35 patients (group 1) who had a failed arthroplasty and 32 patients (group 2) who underwent primary RSA. Clinical outcomes included the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, and range of motion. Complications included radiographic failures (fracture, dislocation, notching, loosening), infections, and nerve palsies.

Results: Group 1 showed significant improvements in flexion and abduction but not in external or internal rotation. Group 2 showed significant improvements in flexion, abduction, and internal rotation but not in external rotation. Both groups showed significant improvements in ASES and SST scores. In group 1, ASES score improved from 24.4 to 40.8 (P = .003), and SST score improved from 1.3 to 3.2 (P = .043). In group 2, ASES score improved from 28.1 to 58.6 (P < .001), and SST score improved from 1.3 to 4.5 (P = .004). The total complication rate was 22.4%. The total reoperation rate was 13.4%, and the revision rate was 8.9%. The implant retention rate was 91% at last follow-up.

Conclusion: RSA in patients younger than 55 years provides significant clinical improvements with high implant retention at up to 12 years. Patients undergoing revision RSA begin with worse function than those undergoing primary RSA, but they can expect similar degrees of improvement. Complications were higher but reoperation rates were lower in the revision group. No mechanical failures occurred in the primary group, with infection the cause of all revisions.