[An experimental analysis of three-dimensional hip joint force after pelvic osteotomies]

A three-dimensional analysis of the resultant forces on the hip was carried out using a fresh cadaver of a 40 year old male. A cross sectional area of each of twenty-four muscles around the hip was measured. Markers were fixed at the proximal and the distal insertions of the muscles and the direction of muscular forces was calculated. From these data, three-dimensional resultant forces on the hip and muscular forces around the hip were calculated through the computer in the normal and the postoperative states of Salter pelvic osteotomy, Chiari pelvic osteotomy and rotational acetabular osteotomy. The results showed the resultant forces to be 3.38 times the body weight in the normal specimen, and 3.79 times for the Salter pelvic osteotomy, 2.74 times for the Chiari pelvic osteotomy, and 4.07 times for the rotational acetabular osteotomy. However, as the loaded area on the femoral head also had increased to 1.12 times for the Salter pelvic osteotomy, and 1.20 times for the rotational acetabular osteotomy, the resultant force in each square centimeter was 0.94 times for the Salter pelvic osteotomy, and 0.71 times for the rotational acetabular osteotomy.