Finite element prediction of contact pressures in cam-type femoroacetabular impingement with varied alpha angles.

Three dimensional finite element models of cam-type FAI with alpha angles of 60°, 70°, 80°, and 90° were created to investigate the cartilage contact mechanics in daily activities. Intra-articular cartilage contact pressures during routine daily activities were assessed and cross-compared with a normal control hip. Alpha angles and hip range of motion were found to have a combined influence on the cartilage contact mechanics in hips with cam-type FAI, thereby resulting in abnormally high pressures and driving the cartilage damage. In particular, alpha angles of 80° or greater contribute to substantial pressure increase under certain types of daily activities.