Biomechanical comparison of component position and hardware failure in the reverse shoulder prosthesis

There has been renewed interest in reverse shoulder arthroplasty for the treatment of glenohumeral arthritis with concomitant rotator cuff deficiency. Failure of the prosthesis at the glenoid attachment site remains a concern. The purpose of this study was to examine glenoid component stability with regard to the angle of implantation. This investigation entailed a biomechanical analysis to evaluate forces and micromotion in glenoid components attached to 12 polyurethane blocks at −15°, 0°, and +15° of superior and inferior tilt. The 15° inferior tilt had the most uniform compressive forces and the least amount of tensile forces and micromotion when compared with the 0° and 15° superiorly tilted baseplate. Our results suggest that implantation with an inferior tilt will reduce the incidence of mechanical failure of the glenoid component in a reverse shoulder prosthesis.