Genu valgus deformity occur when :
In genu valgum or knock-knee deformity, as the mechanical axis shifts laterally, pathological stress is placed on the lateral femur and tibia, inhibiting growth and possibly leading to a vicious cycle. Not only is physeal growth inhibited, but also the Hueter-Volkmann effect upon the entire epiphysis prevents its normal expansion. According to the Hueter-Volkmann principle, continuous or excessive compressive forces upon the epiphysis have an inhibitory effect upon growth. Consequently, growth in the lateral condyle of the femur is suppressed globally, resulting in a shallow femoral sulcus and a propensity for the patella to tilt and subluxate laterally.
Long axis of tibia and fibula moves medial to long axis of femur
Long axis of tibia and fibula moves lateral to the long axis of femur
Long axis of femur is posterior to tibia and fibula
Long axis of femur is anterior to tibia and fibula