Fig. 1

Distal femoral torsion was measured on transverse CT scan at different levels. Two lines are drawn to measure the (A) distal femur torsion (distal femur–posterior condyles), (B) and posterior femoral condyle torsion (clinical transepicondylar axis–posterior condyles). a The PCL is defined as the line connecting the the posterior margin of the lateral and medial femoral condyles. b The CEA is defined as the line passing through the apexes of the medial and lateral femoral epicondyles. c The DFL is defined as the tangent of the posterior part of the distal femur at the upper level of the popliteal fossa. d The ACL is defined as the tangent line connecting the anterolateral condyle of the femur to the apex of the anteromedial condyle. e Diagram of ALC,AMC,PLC and PMC