This report compares the radiologic and early clinical results of total knee arthroplasty (TKA) performed by the same surgeon using 3 techniques. In this prospective study, 75 knees were randomized to conventional technique (25 knees), image-free navigation system (25 knees), or minimally invasive surgery (MIS) (25 knees). Age range of the 43 women (65 knees) and 5 men (10 knees) was 58 to 81 years. Posterior stabilized knee prosthesis was used in all patients. Data was collected according to Knee Society System for radiologic evaluation of x-rays. Knee Society clinical (KS-C) and functional knee scores were measured preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years. The postoperative KS-C was not statistically better in the MIS group (mean, 88 ± 11.5; range, 70-100) than the conventional (mean, 85.9 ± 7.8; range, 74-94) (P=.68) or navigation group (mean, 85 ± 11; range, 63-100) (P=.59). Mean postoperative delta (mechanical axis) angle was significantly different (P=.014): 2.38° in the conventional group (SD=2.88°; 95% CI, 1.19°-3.57°; range, -1.59° to 6.86°), 0.61° in the navigation group (SD=2.07°; 95% CI, -0.24° to 1.46°; range, -2.07° to 4.25°), and 4.25° in the MIS group (SD=6.52°; 95% CI, 1.56°-6.94°; range, -6.72° to 15.60°). Significant difference could be elicited between navigation-assisted and MIS groups, with navigation-assisted surgery providing more accurate alignment of the mechanical axis (P=.014). Of the three techniques, navigation-assisted surgery gives superior prosthesis alignment and promising longevity of TKA.