A photoelastic study of a model of the proximal femur. A biomechanical study of unstable trochanteric fractures I.

In attempt to standardize an experimental model for biomechanical studies of unstable trochanteric fractures, acrylic models of the proximal femur were investigated by the photoelastic technique. By matching the stress distribution in the acrylic models to those calculated by Pauwels, it was found that the optimal femoral shaft and resultant hip joint force angles were 5 degrees and 6 degrees to the vertical, respectively. The abductor muscle pull was determined to be 55 per cent of the resultant hip joint force at 15 degrees medial inclination to the vertical.