Riassunto dello studio

One hundred twenty patients with symptomatic irreparable massive rotator cuff tear, cuff tear arthropathy, or primary osteoarthritis with full-thickness rotator cuff tear were randomized 2:1 to receive an Asian-type reverse shoulder arthroplasty (RSA) implant (n = 80) or a conventional reverse shoulder arthroplasty implant (n = 40). The primary outcome of interest was shoulder function, as measured by the American Shoulder and Elbow Surgeons (ASES) score, with supporting functional measures including Constant score, pain (visual analog scale), and active range of motion. Secondary outcomes of interest included radiographic parameters (acromiohumeral distance, acromion–deltoid tuberosity distance, lateral humeral offset, center of rotation), three-dimensional CT–based baseplate and screw positioning, scapular notching, and acromial stress fracture. Outcomes were assessed preoperatively and at 3, 6, and 12 months postoperatively and at a minimum of 2 years, with CT obtained at 1 year. Overall, the results of the study revealed that both implants produced similar, clinically meaningful improvements in function and pain without significant between-group differences, while the Asian-type implant allowed a more central positioning of the glenoid baseplate on CT. These findings suggest that an Asian-type RSA implant provides equivalent short-term clinical and radiological outcomes to a conventional system in Asian patients, while potentially improving baseplate placement in smaller glenoids.