20 patients suffering from osteoarthritis of the shoulder undergoing total shoulder arthroplasty (TSA) were randomized to either receive TSA using a software assisted navigation procedure or TSA using physician guidance by anatomical land marks. Accuracy of glenoid positioning is an important factor in functional recovery and wear rate of the prosthesis. Software assisted navigation has been hypothesized to provide improved retroversion accuracy. The results from this study support this hypothesis indicating that the software assisted TSA provided improved retroversion accuracy, though it should be noted that there was significant attrition and small sample sizes used in this trial, which limit its application to clinical use.