Comparison of outcomes after reverse shoulder arthroplasty in patients with rheumatoid arthritis and cuff tear arthropathy

Background: The reverse shoulder arthroplasty (RSA) was originally designed for cuff tear arthropathy (CTA). Over time, the indications have expanded to rheumatoid arthritis (RA). This study aimed to compare the outcomes of RSA in patients with RA and CTA to determine if there is any impact on clinical and radiographic outcomes. Methods: In this retrospective comparative study (performed from August 2010 to March 2017), 61 shoulders from 59 consecutive patients (RA group: 24 patients [26 shoulders], CTA group: 35 patients [35 shoulders]) who underwent primary RSA, were included. The average follow-up period was 31 months (range, 24-64 months). Patients were assessed with the use of the visual analog scale pain score, the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, the Single Assessment Numeric Evaluation score, range of motion (ROM), and imaging studies included the 13 angle, glenoid component superior tilt, and scapular notching. Results: The clinical results improved significantly in both groups, but there was no statistically significant difference between the RA group and the CTA group. Significant intergroup differences were observed regarding the 13 angle (73 degrees +/- 11 degrees for the RA group vs. 85 degrees +/- 8 degrees for the CTA group; P < .001) and glenoid component superior tilt (12 cases for the RA group vs. 4 cases for the CTA group; P < .001) at the final follow-up. The Scapular notching was observed in 19 (73%) and 24 (69%) shoulders in the RA and CTA groups, respectively (P = .662). There were 7 (27%) complications in the RA group and 3 (9%) in the CTA group. Fractures involving greater tuberosity, lesser tuberosity, acromion, glenoid, and peri-implant were observed either intraoperatively or postoperatively in 6 shoulders in the RA group and in 3 shoulders in the CTA group. One case of transient musculocutaneous nerve palsy in the RA group was noted. None of the patients required revision surgery for any reason. Conclusion: Compared with CTA patients, RA patients achieved similar clinical outcomes following RSA. However, surgeons should pay attention to the positioning of the glenoid component during the surgery and the risk of intraoperative fractures in RA patients. (c) 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.