Outcomes of anatomic total shoulder arthroplasty in patients with excessive glenoid retroversion: a case-control study

Background: Ideal management of severe glenoid retroversion during anatomic total shoulder arthroplasty (TSA) remains controversial. as previous reports have suggested that severe retroversion may negatively impact clinical outcomes. The purpose of this study was to evaluate the impact of severe glenoid retroversion on clinical and radiographic TSA outcomes using a standard glenoid component, as well as to compare outcomes among patients with less severe retroversion. Methods: A case-control study was performed comparing 40 patients treated with TSA with more than 20 degrees of glenoid retroversion preoperatively (average follow-up, 53 months) vs. a matched cohort of 80 patients with less than 20 degrees of retroversion (average follow-up, 49 months). In all patients, the surgical technique, implant design, and postoperative rehabilitation protocol were identical. Patients were matched based on sex, age, indication, and prosthetic size. Comparisons were made regarding patient-reported outcome measures (PROMs), motion, postoperative radiographic loosening, and the presence of medial calcar resorption. Results: Preoperatively, both groups demonstrated similar PROMs and measured motion, except for preoperative Single Assessment Numeric Evaluation scores and American Shoulder and Elbow Surgeons total scores, which were higher for the severe retroversion group (44.4 vs. 31.3 [P = .012] and 34.9 vs. 29.4 [P = .048], respectively). Postoperative PROMs and motion were also similar between the 2 cohorts. No significant differences were observed for postoperative radiographic findings. Medial calcar resorption was identified in 74 patients (61.7%). Calcar resorption and individual resorption grades were not found to differ significantly. Conclusion: At midterm follow-up, preoperative severe glenoid retroversion does not appear to influence clinical or radiographic outcomes of TSA using a standard glenoid component. (C) 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.