Gait analysis following varus osteotomy of the femur for hip osteoarthritis

The purpose of this study was to evaluate differences in the gait patterns of healthy and osteoarthritic hips, and changes in these patterns after intertrochanteric varus osteotomy of the femur, in relation to the strength of the muscles around the hip joint. We measured the strength ratio of hip abductor muscles, temporal and distance factors, and pelvic movement, and carried out dynamic electromyography (EMG) in 24 women who underwent unilateral varus osteotomy of the femur for hip osteoarthritis (OA), 30 non-surgically-treated women with hip OA, and 54 healthy women. The stance phase time was shorter and the strength ratio of hip abductor muscles was lower in the operated patients than these values in the other two groups, changes in pelvic obliquity and tilt were smaller, and changes in the percent maximum voluntary contraction of the gluteus medius and tensor fascia latae muscles were greater than these values in the healthy subjects. This study showed the postoperative reappearance of the simulated conditions in the hip before varus osteotomy of the femur, providing evidence that the pelvis was horizontally maintained during walking due to the decreased stance phase time and increased performance of the hip abductor muscles achieved after this procedure. Received for publication on March 30, 1998; accepted on Sept. 28, 1998