Subchondral cancellous bone in osteoarthrosis and rheumatoid arthritis of the femoral head. A quantitative histological study of trabecular remodelling.

Thirty-three femoral heads taken from patients undergoing total hip replacement for osteoarthrosis and rheumatoid arthritis have been examined in undecalcified, plastic-embedded sections, using a quantitative histological methods. The characteristic change of trabecular remodelling in the subchonfral cancellous bone of the femoral heads was that total osteoid surface in the medial osteoarthritis (medial O.A.) and rheumatoid arthritis (R.A.) was significantly less than in the proximal osteoarthrosis (proximal O.A.) (P less than 0.01). Resorption surface was slightly greater in R.A. than in proximal O.A. (P less than 0.05). Bone area in the deep area was not different in each group. In the superficial area it was significantly less in medial O.A. than in proximal O.A. (P less than 0.05). The average width of trabeculae was slightly less in medial O.A. and R.A. It is suggested that subchondral trabecular remodelling may be a basic pathological process of general importance in the evolution of these diseases.