Abstract
Uniformity of stress transfer and restoration of femoral head position are essential for long term success in total hip arthroplasty. This study applies a continuous, high speed video digitizing technique to quantitatively assess the three dimensional orientational geometry of the human cadaveric femur and then determine the regional deformation characteristics of the femur under cyclic loading as a function of adduction angle. In geometric assessment of the femur, two dimensional measurements differ from three dimensional measurements. This is true especially in the presence of large femoral head anteversion, where two-dimensional measurements will tend to overestimate neck angle and underestimate neck length. The femoral loading data showed that the femur deformation at 10 plus Q degrees of adduction, was smallest and relatively constant throughout the entire proximal femur, indicating uniform stress transfer. This position of the femur corresponds to the heel strike phase of gate.