Failure Mechanisms After Primary Reverse Total Shoulder Arthroplasty Requiring Revision Reverse Shoulder Arthroplasty

INTRODUCTION Reverse total shoulder arthroplasty (rTSA) has substantially grown in use over the past two decades and is now commonly used for the treatment of cuff tear arthropathy, complex fractures, revision arthroplasty, and rotator cuff insufficiency. Although rTSA demonstrates reliable outcomes, it has a distinct complication profile compared to hemiarthroplasty or anatomic total shoulder arthroplasty (TSA). Prior studies often focus on complication rates rather than the distribution and timing of revision indications. The purpose of this study was to characterize failure mechanisms following primary rTSA and to describe the time from index surgery to revision by indication. METHODS This was a retrospective cohort study of patients undergoing revision of a primary rTSA at a single academic institution between 2013 and 2025. Revision indications were categorized as instability, infection, fracture, hardware complication, aseptic loosening, pain, or stiffness. The primary outcome was the distribution of revision indications. The secondary outcome was the time from index rTSA to revision, reported as median months with interquartile ranges (IQR). RESULTS A total of 179 revision rTSAs were included. The mean age at revision was 69.8 ± 8.9 years, and 44% of patients were female. The median time from index to revision was 13.8 months (IQR 2.3-28.1). Instability was the most common indication for revision (30.7%), followed by infection (19.6%), aseptic loosening (18.4%), and periprosthetic fracture (15.6%). Hardware complications (8.4%) were also notable contributors to revision. Instability (9.1 months; IQR 1.6-19.8), fracture (10.7 months; IQR 3.2-27.6), and hardware complications (8.6 months; IQR 1.7-25.1) occurred early in the postoperative course. By comparison, aseptic loosening (16.5 months; IQR 3.7-28.9) and infection (25.7 months; IQR 5.0-37.0) were associated with longer intervals from index to revision. CONCLUSION Revision following rTSA is most commonly due to early mechanical complications such as instability and fracture. By contrast, infection demonstrated a longer interval to revision, while aseptic loosening showed component-specific timing, with earlier humeral and later glenoid/baseplate failures. Recognition of implant-specific failure timing may improve surgical planning, patient counseling, and postoperative surveillance. Level of Evidence Level IV, Case Series, Prognosis Study