The role of the acetabular labrum and the transverse acetabular ligament in load transmission in the hip.

We performed a biomechanical study of seventeen hip joints in the pelves of nine cadavera in order to assess the role that the acetabular labrum and the transverse acetabular ligament play in load transmission. The distribution of contact area and pressure between the acetabulum and the femoral head was measured with the hip in four different conditions: intact (seventeen hips), after removal of the transverse acetabular ligament (eight hips), after removal of the entire labrum (nine hips), and after removal of both the transverse acetabular ligament and the labrum (seventeen hips). The hip joint was loaded in simulated single-limb stance, and the measurements were made with use of pressure-sensitive film. A peripheral distribution of load was seen in the intact acetabula. This pattern was altered only minimally after removal of the transverse acetabular ligament or the labrum, or both. When both of these structures were removed, the only significant change was a decrease in the maximum pressure in the posterior aspect of the acetabulum (p = 0.02). No significant changes were detected with regard to the contact area, load, mean pressure, or maximum pressure in the anterior or superior aspect of the acetabulum under any testing condition.