Preoperative glenoid retroversion does not influence postoperative outcomes or glenoid lateralization after reverse shoulder arthroplasty at a minimum 2-year follow-up: A retrospective cohort study from the FP-UCBM Shoulder Study Group

Introduction In glenohumeral osteoarthritis, progressive bone erosion often leads to posterior humeral head subluxation and increased glenoid retroversion. Correcting this deformity represents a major challenge in reverse shoulder arthroplasty (RSA), where surgical techniques commonly aim to restore neutral glenoid orientation (0°). Evidence regarding the influence of preoperative glenoid retroversion on postoperative outcomes remains limited. This study aimed to evaluate whether clinical and functional outcomes at a minimum 2-year follow-up differ according to preoperative glenoid retroversion in patients undergoing reverse total shoulder arthroplasty (RTSA) with systematic intraoperative correction to neutral. Methods A total of 161 patients undergoing RTSA were retrospectively reviewed. Preoperative planning was performed using 3D software to restore neutral glenoid orientation via the bony-increased offset reverse shoulder arthroplasty technique. Glenoid retroversion was measured preoperatively on CT scans using the Friedman method, while postoperative glenoid version was assessed on axillary radiographs to confirm neutral orientation. Patients were stratified into two groups based on preoperative retroversion (<10° and ≥10°). Clinical outcomes and range of motion at a minimum follow-up of 24 months were compared between groups. Glenoid lateralization was assessed radiographically using the glenoid lateralization angle (GLA). Group comparisons were performed using the Mann–Whitney U test, and correlations were assessed using Spearman analysis. A p-value < 0.05 was considered statistically significant. Results After exclusion of four patients with postoperative complications, 157 patients were included in the final analysis. The mean postoperative glenoid version was 0.35° ± 0.8° (range, −1° to +2°). No significant differences were observed in any clinical outcome between patients with <10° and ≥10° of preoperative glenoid retroversion, and no significant correlations were found between preoperative retroversion and postoperative outcomes. Radiographic analysis confirmed restoration of near-neutral glenoid version in all patients and demonstrated comparable glenoid lateralization between groups, with no significant differences in the GLA. Conclusion In glenohumeral osteoarthritis, the most common pattern of bone loss results in increased glenoid retroversion and posterior humeral head subluxation. It remains debated whether, when applying standard correction techniques aimed at restoring neutral glenoid version, the severity of preoperative glenoid retroversion influences postoperative outcomes. The findings of this study indicate that, when RSA is performed with restoration of neutral glenoid version, postoperative clinical and functional outcomes are independent of the degree of preoperative glenoid retroversion. Level of evidence Level III cohort study