[Experimental study on the development of aseptic necrosis of femoral head--with comparison of osteoarthritis of the hip in collagen metabolism].

Collagen analysis of articular cartilage and subchondral bone was performed on femoral heads obtained from patients of late stage of aseptic necrosis (ANF) (4 cases), and osteoarthritis (OA) (7 cases). In articular cartilage of both diseases, there was not observed any difference in the solubility of collagen compared with normal articular cartilage. However, collagen contents determined by hydroxyproline analysis showed a decrease in both diseases; this tendency was prominent in OA. On the other hand, copper contents showed an increase in ANF while there was a decrease in OA; the fact may suggest that lysyl oxidase acts actively on the formation of a precursor of cross-links in collagen matrix of articular cartilage in ANF. In subchondral bone of both diseases, collagen contents showed an increase in OA, and a decrease in ANF compared with normal subchondral bone. However the solubility of collagen has increased in both diseases. Moreover, lysine hydroxylation and copper contents showed an increase in both OA and ANF; these findings suggest that repairing reaction of the pathological lesion by proliferation of undifferentiated tissue remained even in late stage of the disease. In this paper, the author also discussed about the connective tissue metabolism of these two diseases by determination the types of collagen molecules of pathological cartilage and bone.