To compare radiologic measurements of femoral and tibial component position in the total knee replacement (TKR) using computer-assisted surgery (CAS) with those of conventional TKR.

Two groups of 40 TKRs each were operated on using a CT-free navigation system or the conventional technique. Patients in both groups were matched according to age, gender, diagnosis, prosthesis and PCL retaining or substitution. We measured femoral component frontal (alpha angle) and sagittal angle (gamma angle), tibial component frontal (beta angle) and sagittal angle (delta angle). We also studied whether femoral notch was present or not.

There were no significant differences in alpha angle, beta angle, delta angle and femoral notch between CAS and conventional TKR (p>0.05). The mean delta angle in the group of TKRs using CAS was 0.28±1.96 °, and in the group of conventional TKRs was 2.39±2.73°(p<0.0001). This difference was statistically significance.

Our study has shown that there were no significant differences in alpha angle, beta angle, delta angle and incidence of femoral notching between CAS TKR and conventional TKR. Gamma angle was different statistically between CAS TKR and conventional TKR. The CAS afforded to precisely place femoral component in sagittal plan than conventional method.