Morphometric analysis of subchondral bone of the tibial condyle in osteoarthrosis

Tibial condyles in 11 patients with knee joint osteoarthrosis were analyzed by subchondral bone morphometry using 11 static parameters. The results were evaluated by comparison with the grade of joint cartilage degeneration in relation to the external, intermediate, and internal areas of the tibial condyle. The bone morphometric data also were analyzed according to the depth of layers, from the surface to the depth of 2000 microns of the bone. A parallel relationship between the bone volume/bone formation activity and the Mankin grade of cartilage degeneration was noted in both medial and lateral condyles. Bone resorption activity in the medial condyle was found only in the external and intermediate areas; it was extremely low in the lateral condyle. Throughout the observation areas, the values of bone volume in relation to depth were highest in the superficial layer with a gradual decrease as the depth increased. The bone formation activity was highest in the superficial layer in the lateral condyle, whereas in the medial condyle, it was highest in the layer between 1000 and 1500 microns in depth. The bone resorption activity showed no variations according to the depth. The progression of joint cartilage degeneration was associated with remodeling of the underlying subchondral bone.