gms | German Medical Science

Objectives: For degenerative shoulder disease, reverse shoulder arthroplasty (RSA) has proven successful; however, problems such as scapular notching and instability still exist. These difficulties are intended to be addressed by recently improved prosthesis designs with reduced neck-shaft angles (NSA). Still, there are issues with complications, particularly with the humerus. In an effort to avoid these problems and maintain bone stock, a recently designed straight-short-stem humeral component was used; however, little is known about its clinical and radiological results in RSA, yet its clinical and radiological outcomes in RSA remain largely unexplored.

Methods: Using a 55 mm straight short stem, a retrospective analysis of 100 patients undergoing primary RSA was carried out. Clinical assessments, including scores and range of motion, were conducted both before and after surgery. Complications, bone adaptation, and stem alignment were all evaluated radiographically. Significant correlations between postoperative shoulder movements and function and were correlated with angels of prosthesis lateralization and distalization .

Results: Clinical scores showed a significant improvement at an average 30-month follow-up. Radiographs showed bone adaptation without stem loosening. Regression models revealed non-linear relationships between specific shoulder movements and angles, emphasizing optimal ranges for elevation and external rotation. Complications were minimal (5%) and included rare instances of aseptic loosening and fractures.

Discussion and conclusion: This study validates the efficacy of the straight short stem in improving clinical outcomes and implant stability in RSA. Notably, it demonstrates specific angle ranges crucial for optimal post-surgical shoulder function. The findings suggest this stem design's potential benefits in RSA, highlighting its safety and effectiveness while providing insights for future clinical strategies. The study contributes valuable data toward understanding and enhancing patient outcomes in shoulder arthroplasty procedures.