Reexamination of hip biomechanics during unilateral stance.

The Koch model, as initially proposed, is an incomplete representation of hip biomechanics during the unilateral support phase of midstance. The model proposed by this study includes the iliotibial band as a tension band lateral to the femoral shaft. During the unilateral support phase of gait, the iliotibial band creates compression loading laterally and medially throughout the femur distal to the greater trochanteric apophysis. Bench testing of cadaveric femora with and without protheses demonstrated the necessity of a total hip replacement femoral component to engage the proximal lateral femoral cortex as an additional area of support against subsidence. This model, byproviding a more complete and accurate depiction of hip biomechanics, creates a more valid basis for analysis of hip function.