Surgical and patient factors associated with baseplate failures after reverse shoulder arthroplasty: a study by the ASES Complications of RSA Multicenter Research Group

Abstract

Background: Baseplate failure is a rare but serious complication following reverse shoulder arthroplasty (rTSA), often leading to poor outcomes and revision surgery. Existing studies are limited by small samples or single-center designs. This multicenter study aimed to identify surgical, implant, and patient-related risk factors for baseplate failure after rTSA. Methods: A multicenter, retrospective study was conducted across 15 U S. institutions involving 24 ASES surgeons. Patients who underwent rTSA from June 2013 to May 2019 with a minimum 3-month follow-up were included. Study parameters were established using the Delphi method. Patients with confirmed baseplate failure were compared to those without using univariate and multivariable logistic regression analyses. Failure was defined radiographically as gross baseplate shift or hardware breakage. Results: Among 5,049 cases, 83 (1.6%) experienced baseplate failure at a median of 72 weeks post-surgery. Most failures (76%) were atraumatic; 12% were traumatic, and 12% had an unknown mechanism. Radiographs showed hardware breakage in 68.7% of the failures—33.3% involved central screw/post fractures and 86.0% involved peripheral screw fractures. Baseplate shift occurred in 78.3% of cases. Independent predictors of failure included revision arthroplasty (OR = 4.57; P < .001), use of bone graft (OR = 2.81; P < .001), and total glenoid-sided lateral offset (OR = 1.08; P = .002). Central screw fixation reduced failure risk (OR = 0.55; P = .014). In primary rTSA, bone grafting (OR = 4.42; P < .001) and lateral offset (OR = 1.07; P = .046) were significant predictors. In revision rTSA, only bone grafting remained significant (OR = 3.75; P < .001). Allograft use led to higher failure rates than autograft (14.7% vs 3.9%; P = .001). Conclusion: Revision surgery, bone grafting (especially allografts), and increased lateral offset were significantly associated with higher odds of baseplate failure after rTSA. Central screw fixation appears protective. Most failures were atraumatic, underscoring the importance of achieving stable bone ingrowth. These findings may inform surgical planning and patient counseling regarding factors associated with increased failure risk.