110 patients undergoing total hip arthroplasty were randomized to have their leg length measured intraoperatively using either a computer navigation tool or an outrigger device. The purpose of this study was to compare the accuracy and precision of these two methods in determining intraoperative leg length changes, as measured by the difference between intraoperative measurements and pre- and post-operative radiographs. The results displayed similar accuracy and operative time between groups, however, the computer navigation tool was more precise as determined by the greater proportion of patients with an intraoperative change in leg length within 5mm of the radiographic measurement.