Reverse shoulder arthroplasty with and without baseplate wedge augmentation in the setting of glenoid deformity and rotator cuff deficiency—a multicenter investigation

Abstract

Glenoid baseplate augments have recently been introduced as a way of managing glenoid monoplanar or biplanar abnormalities in reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the difference in clinical outcomes, complications, and revision rates between augmented and standard baseplates in RSA for rotator cuff arthropathy patients with glenoid deformity. A multicenter retrospective analysis of 171 patients with glenoid bone loss who underwent RSA with and without augmented baseplates was performed. Preoperative inclusion criteria included minimum follow-up of 2 years and preoperative retroversion of 15°-30° and/or a beta angle 70°-80°. Version and beta angle were measured on computed tomographic scans, when available, and plain radiographs. Shoulder range of motion (ROM) and patient-reported outcomes were obtained from preoperative and multiple postoperative time points. The study consisted of 84 standard baseplate patients and 87 augmented baseplate patients. The augment cohort had greater mean preoperative glenoid retroversion (17° vs. 9°, P<.001). At >5-year follow-up, the increase in postoperative active abduction (52° vs. 31°, P=.023), forward flexion (58° vs. 35°, P=.020), and internal rotation score (2.8° vs. 1.1°, P=.001) was significantly greater in the augment cohort. Additionally, >5-year follow-up American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score (87.0±16.6 vs. 75.9±22.4, P=.022), Constant score (78.0±9.7 vs. 64.6±15.1, P<.001), and Shoulder Arthroplasty Smart score (81.2±6.5 vs. 71.2±13.6, P=.003) were significantly higher in the augment cohort. Revision rate was low overall, with no difference between the augment and no augment groups (0.7% vs. 3.0%, P=.151). In comparing augments to standard nonaugment baseplates in the setting of RSA with glenoid deformity, our results demonstrate greater postoperative improvements in multiple planes of active ROM in the augment cohort. Additionally, the augment cohort demonstrated greater postoperative level and improvement in scores for multiple clinical outcome metrics up to >5 years of follow-up with no difference in complication or revision rates, supporting the use of augmented glenoid baseplates in RSA with glenoid deformity.