Fig. 2

Intraoperative tibial rotation relative to the femur in elderly (aged ≥75 years) and nonelderly patients (aged < 75 years). Intraoperative tibial rotation was defined as the angle between the tibial anteroposterior (AP) axis and the femoral AP axis in axial plane and, tibial internal rotation relative to the femur was defined a plus value. The tibial internal rotational angles during the entire knee flexion and from 90° to full flexion were significantly larger in nonelderly patients