75 knees undergoing total knee arthroplasty were randomized to undergo the procedure with a conventional technique, an image-free navigation system technique, or a minimally invasive technique. Patients in the groups were assessed radiologically and with the Knee Society clinical and functional knee scores over 2 years. The navigation-assisted surgery group showed significantly better results for the mean delta mechanical axis angle compared to minimally invasive surgery, but there were no differences compared to the conventional group. There were no significant clinical or functional differences between the three groups.