Loading model for the human femur taking the tension band effect of the ilio-tibial tract into account.

A loading model permitting the application of relevant loads to the diaphysis and constructed on the basis of current knowledge of the biomechanics of the femur will be presented. This model takes into account the force acting through the ilio-tibial tract in the frontal plane and the forces acting on the condyles in the sagittal plane. There is compression on the femoral head and on the condyles and tension on the greater trochanter. Experimental verification using human cadaveric femora instrumented with strain gauges has shown that the adequate loading condition is: a line of force tangential to the femoral head a line of force tangential to the dorsal aspect of the distal junction of the diaphysis and metaphysis. Under these conditions, the calculated forces will accord well with values assessed in vivo. The model described here represents a simple procedure for experimental load application, producing realistic strain values. The proximal part of the bone is placed under tension on the dorsal aspect; the medial aspect is under compression. The strain pattern develops such that the tensile forces affect the anterior aspect distally and compression the dorsal aspect.