Osteoarthritis (OA) of the shoulder is a disease resulting from the wearing down of cartilage over time. OA can produce pain and dysfunction at the affected joint and is a growing occurrence in an aging population. Total shoulder arthroplasty (TSA) is a surgical treatment used to treat patients with shoulder OA which involves replacing the worn-out ball and socket shoulder joint with prosthetic components. TSA is performed today with high success rates, however, complication rates associated with TSA remain prevalent particularly when the arthritis is associated with bone erosion on the glenoid (socket). Given the high rate of revisions associated with TSA treatment in the setting of glenoid bone erosion, a number of surgical strategies have been developed. These surgical techniques include eccentric reaming which involves removing bone from the front of the socket, augmented glenoid component implantation, and posterior bone grafting to compensate for glenoid bone loss, and reverse shoulder arthroplasty. Few research studies have compared these different surgical techniques to one another. Previous studies have been limited to case series with small sample sizes and respective designs. This study is being conducted to determine which approach produces better outcomes. For the purpose of this study we will be comparing total shoulder arthroplasty techniques a) augmented glenoid component and eccentric reaming and b) augmented glenoid component and bone grafting in participants with advanced glenohumeral osteoarthritis.