Transepicondylar axis accuracy in computer assisted knee surgery: A comparison of the CT-based measured axis versus the CAS-determined axis

Figures & data

Figure 1. Screen of the navigation system during registration of the epicondyles of the femur. [Color version available online.]

Figure 2. The position of the femoral component, showing the calculated position relative to the rotation axis. [Color version available online.]

Figure 3. Example of a CT slice (1 mm thick) of the distal femur (blue dotted line = CT-based transepicondylar line; red dashed line = line pointed and marked by tantalum markers; purple solid line = posterior condylar line). The angles between the CT-based and pointed lines and the posterior condylar line were measured. [Color version available online.]

Figure 4. A plot of the differences in measurements obtained with the two PCA methods (red line = average difference of 3.18°; upper red dashed line = +2 standard deviation; lower red dashed line = −2 standard deviation [SD = 3.67°]). [Color version available online.]