Anatomic total shoulder arthroplasty revised to reverse total shoulder arthroplasty: clinical and radiographic outcomes compared to primary reverse total shoulder arthroplasty

Background: Reverse total shoulder arthroplasty (rTSA) has become the procedure of choice for a failed anatomic total shoulder arthroplasty (aTSA). Little data exist regarding outcomes; the few studies published to date have small numbers, short follow-up, and most do not have a control group or use first-generation implants. The purpose of this study is to compare the clinical and radiographic outcomes of failed aTSA revised to rTSA to primary rTSA. Methods: A prospective multicenter shoulder registry was used to conduct a retrospective review of patients who received a primary rTSA for osteoarthritis and rotator cuff disease and compare them to those who had an aTSA revised to a rTSA using the same implant between 2007 and 2021 with a minimum follow-up of 2 years. Cohorts were matched 3:1 (primary-to-revision) by age, gender, body mass index, and length of follow-up. Those who underwent revision for humeral fracture, infection, or an unknown reason were excluded. Preoperative and postoperative range of motion and patient-reported outcome measures (PROMs) were compared. Outcomes included rates of scapular notching, complications, revision, and patient satisfaction. Results: There were 88 aTSAs revised to rTSAs compared with 264 matched primary rTSAs. In both cohorts, the mean age was 68 years, 59% were female, and the mean follow-up was 56 months. The most common reason for revision was rotator cuff tearing (53%), followed by aseptic glenoid loosening (34%), instability (9%), aseptic humeral loosening (6%), and glenoid component dissociation (3%). At latest follow-up, patients in both groups had statistically significant improvements in all outcome scores, exceeding the minimal clinically important difference (MCID) and the substantial clinical benefit (SCB). The revision cohort had significantly less postoperative abduction (P <.001) and forward elevation (P = .001) compared with the primary rTSA cohort. All PROMs in the revision cohort were significantly worse than those in the primary rTSA cohort. Patient satisfaction rate in the revision cohort was significantly lower than the primary cohort (P <.001). Complication (P = .005) and revision rates (P = .013) were significantly higher in the revision cohort, whereas scapular notching was similar. Conclusion: Patients undergoing revision of a failed aTSA to rTSA have worse clinical outcomes compared with those undergoing primary rTSA, including all PROMs, abduction, elevation, pain relief, and patient satisfaction, with higher complication and revision rates. Although patients in the revision group had significant improvements that exceeded the MCID and SCB, they do not achieve the same outcomes as patients who undergo primary rTSA.