[Bone structure in aseptic necrosis of the femoral head by light microscopy, contact microradiography, and fluorescent microscopy --comparing with osteoarthritis and rapidly destructive coxarthrosis].
In order to obtain further information of the pathological changes and bone structure of aseptic necrosis (AN), the present author carried out histological investigation on 20 femoral heads removed by prosthesis or total hip replacement from 18 patients. Both decalcified and undecalcified sections were investigated by microscopy, contact microradiography (CMR) and fluorescent microscopy. Schemata of individual cases were drawn to know the relationship between femoral head deformity and bone reactivity. Moreover, 19 femoral heads with secondary osteoarthritis (OA) removed from 18 patients and 7 with rapidly destructive coxarthrosis (RDC) from 6 patients were similarly investigated to compare with AN. The following results were obtained; Histologically, there are four different areas in AN. From the top of the femoral head, the lesion consisted of (1) subchondral necrosis, (2) granulation tissue, (3) an area of variable bone formation, and (4) normal bone tissue. As the advancement of the head deformity, fibrous component in the granulation increases and seems to divide the femoral head into necrotic and living areas, which by fibrous as well as enchondral ossifications become more prominent in the edge of the demarcation. As for the bone formation, four different types of bone tissues are discernible by CMR; (1) low calcified appositional bone and its absorption, (2) low calcified, appositional bone on wide trabeculae, (3) low calcified appositional bone on narrow trabeculae, and (4) irregularly calcified woven bone. Although during the comparatively early stage, the bone formation is seen in almost all of the living area, as the advancement of the head deformity, its activity decreases and results in overt head deformity to resemble that of OA which would be caused by mechanical factor. Increase of fibrous component in the granulation along with decrease of the bone formation would reduce the repairing activity of the femoral head. In the femoral heads with OA, a wedge-shaped area of bone formation is formed of which peak is located on the medial thickened cortex. In the femoral heads with RDC, a large amount of woven bone with irregular calcification is found in the bone formation area, in the upper part of a femoral head.
D000328:Adult; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology / Q000648:ultrastructure; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000473:pathology*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D008852:Microradiography; D008853:Microscopy; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology*