The subchondral bone of the proximal tibial epiphysis in osteoarthritis of the knee.

The trabecular bone of the proximal end of the tibia was assessed as an endoprosthesis-bearing structure. The mass and mineral content as well as the activity of subchondral trabecular bone were determined in osteoarthritis knees with varus or valgus deformity. Bone specimens were taken from the lateral condyle, the medial condyle, and centrally from the intercondylar area of seven varus and four valgus knees. The percentage volume of trabecular bone was determined by histomorphometry. On an additional nine knees, five with varus and four with valgus deformity, as well as ten knees from a normal autopsy material, photon absorptiometric determination of the mineral content of the same areas was performed. On average, the loaded condyle had twice the percentage volume of trabecular bone, and accordingly twice the mineral content, of the unloaded condyle. It was remarkable that the mineral content of the latter was of the same order as the condyles of the normal material.