Outcomes of Reverse Shoulder Arthroplasty in Patients with Os Acromiale: A Systematic Review

Background When the acromion does not fully fuse during development, the resulting condition is known as os acromiale. Since the deltoid muscle, a key player in Reverse Shoulder Arthroplasty (RSA), attaches to the acromion, surgeons may be hesitant to implant an RSA in these patients. Hence, the aim of this study is to report the clinical and radiological outcomes, as well as safety and effectiveness of RSA in patients with os acromiale. Methods A systematic review of the literature was conducted to evaluate the outcomes of RSA in patients with os acromiale, according to PRISMA guidelines. Four studies with a total of 100 patients (103 shoulders) were reviewed. Data on clinical outcomes, range of motion, pain relief, and complications were reported. Results Patients with os acromiale undergoing RSA showed significant improvements in clinical outcomes. The mean weighted postoperative Constant-Murley Score was 69 points, with improved range of motion. In 38.8% of cases a postoperative acromial tilt was reported, however this did not significantly affect the outcome. Conclusions RSA can be considered a safe and reliable procedure for patients with os acromiale, offering improvements in both pain and function, similar to those observed in patients without os acromiale. More than one-third of patients (38.8%) experience os acromiale tilting, which did not show clinical relevance.