Functional deficiencies following reverse and anatomic total shoulder arthroplasty: detecting true differences

Background: Reverse total shoulder arthroplasty (rTSA) has gained traction as a reliable treatment option for glenohumeral osteoarthritis (GHOA). Much of this pivot from anatomic total shoulder arthroplasty (aTSA) to rTSA has centered on the described lower revision rates in the latter, as well as the reported equivalence in composite patient-reported outcomes between the two modes of TSA. Yet, this fails to highlight the nuanced effects each can have on everyday activities. This retrospective study aims to identify specific tasks that remain difficult for patients after TSA for GHOA and assess the difference in ability to perform specific daily tasks between aTSA and rTSA for GHOA. Methods: Patients with minimum 2-year follow-up after undergoing TSA for GHOA were identified from a single-institution registry. Patient-reported outcome data from the American Shoulder and Elbow Surgeons (ASES), Western Ontario Osteoarthritis of the Shoulder (WOOS) index, and Single Assessment Numeric Evaluation surveys were collected at 2-year follow-up. Composite scores as well as each individual component score were compared between the two arthroplasty types by univariate analysis. When a difference in a component was found, further analysis was performed using multivariate linear regression (WOOS) or a multivariate logistic regression (ASES), while controlling for potential confounding variables. All analyses were performed in SPSS (version 28.0; IBM; Armonk, NY, USA). Results: 317 TSAs were identified with two-year follow-up (mean age 67.2 years, 53.9% males), with 219 being anatomic TSA (69.1%). Postoperatively, there was gross improvement in visual analog scale pain (P < .001) and ASES scores (P < .001), with improvements noted in each ASES functional component (P < .001). No differences were noted in all composite survey scores between aTSA and rTSA (P > .15). Across the entire cohort, there was continued difficulty with behind-the-back and overhead activities. While rTSA patients reported better postoperative stiffness (P = .02), they also noted more difficulty in tasks including washing their backs/doing up a bra (ASES, P = .001), tucking in a shirt (WOOS, P = .01), styling hair (WOOS, P = .02) and lifting 4.54 kg (10 lbs) above shoulder level (ASES, P = .001). Even when adjusting for confounding variables, rTSA was an independent predictor for decreased ability to tuck in shirt (WOOS, P < .001) and put on a coat (ASES; P = .03) Conclusion: This study illustrates the subtle differences in postoperative function in patients treated with aTSA versus rTSA for GHOA, most notably in overhead and behind-the-back activities. This knowledge provides surgeons and patients with greater understanding of the true differences in anticipated outcomes between anatomic and reverse TSA for the treatment of GHOA.