The importance of range of motion after total hip arthroplasty

Unlike the knee, range of motion has been of questionable value in evaluating clinical outcome after THA. We retrospectively analyzed the ranges of motion (flexion, abduction, adduction, external rotation, internal rotation, and flexion contracture) of 1383 patients (1517 hips) having primary THA. We recorded Harris hip score components for walking distance, stair climbing, socks and shoes, sitting, pain, presence of limp, and use of support devices. Postoperative hip motion was defined as high (115 degrees of flexion, 25 degrees of abduction, 20 degrees of external rotation, and less than 20 degrees of flexion contracture), average (90 degrees -114 degrees of flexion, 16 degrees -24 degrees of abduction, or 11 degrees -19 degrees of external rotation, and less than 20 degrees of flexion contracture), or low (less than 90 degrees of flexion, 15 degrees or less of abduction, 10 degrees or less of external rotation, or 20 degrees or more of flexion contracture) motion. We correlated this with high, average, or poor postoperative Harris hip scores. Hip motion was found to be correlated with postoperative hip function and may be more useful than previously thought in evaluating hip outcome.