This study involves a novel prospective, multi-center randomized controlled trial of shoulder arthritis candidates randomized to leukocyte-poor platelet-rich plasma (LP-PRP) and corticosteroid (CSI) groups for comparative analysis of patient satisfaction scores and clinical outcomes. These results may delineate the utility of LP-PRP as an intermediary treatment modality in sub-surgical candidate’s refractory to conventional measures. This multi-center prospective randomized study will be the first to evaluate the potential benefit of PRP in the treatment of glenohumeral osteoarthritis in young patients not yet candidates for arthroplasty surgery.