Radiographic study on the natural history of advanced osteoarthritis of the hip joint

We investigated the radiographic changes in 22 hip joints of 17 patients with secondary advanced osteoarthritis of the hip who received conservative treatment for more than 10 years. Arthritic changes progressed in 16 out of 22 joints (73%) and the remaining six joints (26%) did not change. Remodeling occurred in 15 of the hips (68%). During this process, joint congruity improved markedly in eight hips, so the number with good joint congruity increased from 13 (59%) to 21 (95%). In the remaining one hip, remodeling did not occur and joint incongruity was persistent. In this series, there were four radiographic patterns. One pattern was that the hip maintained good joint congruity without progression of osteoarthritis for more than 10 years (five joints, 23%). The second pattern was that hips with good joint congruity initially improved further after remodeling (eight joints, 36%). The third pattern was that hips with joint incongruity initially underwent remodeling to achieve good joint congruity with the passage of time (eght joints, 36%). The fourth pattern was that one hip showed persistent joint incongruity without remodeling (one joint, 5%). Clinically, hip pain did not worsen significantly, but moderate (approximately 70% decrease) limitation of flexion and abduction occurred eventually. These findings suggest that some patients with advanced osteoarthritis of the hip with good joint congruity or hips showing remodeling may be suitable for conservative treatment, especially in younger patients.