Fig. 3

Radiographic variables for the alignment of the lower extremity, the knee and ankle. A The hip-knee-ankle angle was determined as the angle between the mechanical axis of the femur and tibia. B Mechanical lateral distal femoral angle was determined as the angle between the mechanical axis of the femur and the line connecting distal femoral condyles. Medial proximal tibia angle was determined as the angle between the mechanical axis of the tibia and the tangent line of the proximal tibial plateau. Mechanical lateral distal tibial angle was determined as the angle between the mechanical axis of the tibia and the tangent line of the superior surface of the talus. C Joint line convergence angle was determined as the angle between the tangent lines of the distal femoral condyles and the proximal tibia plateau. Knee joint line obliquity was defined as the angle between the tangent line of the proximal tibial plateau and the ground surface line. D Posterior tibial slope was determined as the angle between the proximal tibial plateau and the line connecting the midpoint of 5 cm and 15 cm distal from to knee joint line. E Talar tilt angle was determined as the angle between the tangent lines of the distal surface of the tibia and the superior surface of the talus. Lateral distal tibial ground surface angle was defined as the angle between tangential line of the distal surface of the tibia and the ground surface line. Ankle joint line obliquity was determined as the angle between the tangent line of the superior surface of the talus and the ground surface line