Grammont humeral design versus onlay curved-stem reverse shoulder arthroplasty: comparison of clinical and radiographic outcomes with minimum 2-year follow-up.

BACKGROUND: There are few investigations comparing lateralized and medialized reverse total shoulder arthroplasty (RTSA) in patients with cuff tear arthropathy. This study assessed the outcomes of 2 RTSA designs.
METHODS: Sixty-eight consecutive cuff tear arthropathy patients (74 shoulders) with a follow-up of at least 24 months received a Grammont or an onlay curved short-stem humeral component, with or without glenoid lateralization; a cementless humeral stem was implanted in >90%. Clinical outcome measures included active range of motion (anterior and lateral elevation, external and internal rotation), pain, and the Constant-Murley score. Radiologic outcomes included radiolucency, condensation lines, cortical thinning, spot weld, loosening and subsidence, and tuberosity resorption for the humeral component and radiolucency, scapular notching, formation of scapular bone spurs, ossifications, and loosening for the glenoid component.
RESULTS: Both prostheses provided significant differences between preoperative and postoperative scores and showed a similar complication rate. Scapular fractures were found only in the patients who received the curved short-stem implant. Glenoid bone grafting did not significantly affect clinical scores. Both implants provided similar postoperative shoulder mobility, even though the lateralized curved stem was associated with higher delta scores for external rotation (P = .002) and lower rates of scapular notching (P = .0003), glenoid radiolucency (P = .016), and humeral bone remodeling (P = .004 and P = .030 for cortical thinning and spot weld, respectively).
CONCLUSIONS: Medialized and short-stem lateralized RTSA implants provided similar midterm clinical outcomes and range of motion. The curved short stem was associated with higher delta scores for external rotation and a lower rate of radiographic risk factors.