The purpose of this study was to evaluate the use of a navigation device in a cohort of 42 total knee arthroplasties (TKA). The patients were randomised into two groups. Total knee arthroplasties performed using the conventional technique formed the control group (21 knees); the experimental group included 21 knees performed with the aid of a computed navigation system. Postoperative mean values for the various measurements showed no significant difference in component alignment. However, the range of individual measurements for coronal and sagittal plane positioning was smaller in the navigated group, in which there were no outliers. Rotational alignment was not different between the two groups. This confirms the advantages and limitations of navigated TKA presented in larger studies.