Fig. 2

The femorotibial angle (FTA) is the angle between the anatomical axes of the femur and tibia (a), the hip-knee-ankle angle (HKAA) is the angle between the mechanical axes of the femur and tibia (b), and AJLMA is the angle between the joint-line and the line perpendicular to the mechanical axis (c right, asterisk). A dotted box in the left is magnified in the right. MA, mechanical axis; JL, joint line