Introduction. Reverse shoulder replacement is a surgical option for cuff tear arthropathy. However scapular notching is a concern. Newer designs of glenospheres are available to reduce scapular notching. Eccentric glenosphere with a lowered centre of rotation have been shown to improve range of adduction in vitro. We hypothesize that the eccentric glenosphere improve clinical outcomes and reduce scapular notching. Method. This is an ongoing randomized controlled double blind prospective clinical trial. Patients 70 years or older at North Shore hospital who have a diagnosis of cuff tear arthropathy and require surgery were consented for this study. Patients were allocated a concentric or eccentric 36 mm glenosphere intraoperatively, using a computer generated randomization contained in a sealed envelope. The surgical technique and post operative rehabilitation were standardized. Patients were followed up by a research nurse and postoperative radiographs were also taken at regular intervals. Clinical assessment include a visual analogue pain score, subjective shoulder rating, American Shoulder and Elbow Society Score, and Oxford shoulder score. Complications were checked for and radiographs were assessed for scapular notching. Results. There were 23 patients in the concentric and 24 patients in the eccentric glenosphere group. Average age and duration of follow up were comparable. There was no statistical significant difference but there was a trend towards better functional outcome and better range of motion in the eccentric glenosphere group. There was no scapular notching in the eccentric and three cases of scapular notching in the concentric glenosphere group. Conclusions. Reverse shoulder replacement significantly improve pain, function and range of motion in patients with cuff tear arthropathy. Eccentric glenosphere prevents scapular notching in the SMR reverse prosthesis