In the experimental group (n = 55), three serial slices of CT images, including medial and lateral epicondyles, were merged into a single image, and SEA was overlaid. SEA was traced onto an image of an assumed distal femoral resection level; this combined image was then printed out onto a transparent film as a CT template. Following a distal femoral resection in TKA, SEA was duplicated onto the femoral surface. Thereafter, the posterior condyle was resected parallel to this SEA. In the control group (n = 53), posterior condyles were resected at three degrees of the external rotation from the posterior condylar line (PCL).
A posterior condylar angle (PCA) between PCL of the femoral component and SEA was postoperatively evaluated. Positive values indicated external rotation of the femoral component from the SEA.