Computer-assisted surgery: a teacher of TKAs

The hypothesis of this study is that computer-aided navigation experience could improve the ability to better place components in the coronal plane and to improve visual/spatial awareness based on the ability of navigation to provide instant feedback. The purpose of this study is to demonstrate the educational role of the navigation system to obtain a better alignment of the prosthetic components with standard instrumentation after a computer-aided navigation experience.

One hundred fifty patients were operated by the same surgeon, with more than 5 years experience with TKA. They were equally divided in three groups: group A (operated with non-navigated technique by surgeon without computer-assisted experience); group B (operated with computer-assisted surgery by the same surgeon); group C (operated with non-navigated technique by the same surgeon after the computer-navigated experience). We evaluated by full-length weight-bearing radiographs the overall alignment of the lower limb in the coronal plane. The optimum placement of the components was considered when the angle was within the limits of ±3° varus/valgus on the coronal x-rays. Comparison between groups was done using one-way ANOVA followed by post hoc Bonferroni test and Pearson chi-square statistics for proportions of optimum placement (P<0.05).

In the group A 34 patients (68%) had the optimum placement on the coronal x-rays; in the group B they were 46 (92%) and in the group 41 (82%). The difference is statistically significant in comparing group A and Group B (<0.001), group A and group C (P=0.04), but not for group B and C (P=0.2).

We believe that the navigation system has an educational role to improve the ability of surgeon of positioning prosthetic components precisely in the coronal plane.