To compare the radiologic and clinical outcomes of total knee arthroplasty (TKA) performed using a navigation system with those obtained using the conventional technique.

Forty-one TKAs were performed using a navigation system (navigation group) and forty-eight by conventional surgery (conventional group). Radiologic results outside the range defined by ±3° of optimum were classified as outliers. Range of motion and HSS scores at final follow-up were also compared.

Mean mechanical axes were 0.3° valgus for navigation and 0.5° varus for the conventional group, which were not statistically different. However, two outliers occurred in the navigation group, which was significantly less than the 14 that occurred in the conventional group. Mean coronal inclination of the femoral component was significantly different in the two groups as were the outlier numbers. Although outlier numbers significantly differed in sagittal inclination of the femoral or tibial components or coronal inclination of the tibial component, there were no statistical differences in terms of mean values. Differences in ROM and HSS scores were also not observed between the two groups.

The navigation system helped increase alignment accuracy of the lower extremity, but no significant difference was observed in clinical results between the two study groups.