Influnence of posterior wall fractures of the acetabulum on the pressure between the acetabulum and the femoral head

Objective To evaluate the effect of the acetabular fractures of posterior wall on the pressure between the acetabulum and the femoral head. Methods Six embalmed pelvis and articulated proximal 1/3 of the femurs were harvested for this study. The position of the pelvis and proximal femur during testing simulated the single leg stance phase of gait. The pressure sensitive films recorded the pressure, and the distribution of the pressure between the acetabulum and the femoral head. Testing was initially performed with the intact acetabulum. After the intact patterns were recorded, the 1/3,2/3, and 3/3 fracture of the posterior wall were tested. Results After the posterior wall fracture of the acetabulum, the pressure of the weight bearing dome was significantly increased ( P 0.01 ). The pressure of the anterior wall was significantly decreased ( P 0.01 ). There was no significant effect on the pressure of the remained posterior wall. Conclusions The posterior wall fractures of the acetabulum significantly alter the pressure between the acetabulum and the femoral head. The pressure of the hip joint is redistributed after the posterior wall fractures. The one third fracture of the posterior wall results in the greatest alteration in joint pressure.