Abstract
In order to elucidate the pathogenesis of ANFH, 26 femoral heads were examined pathologically. Nine heads from 8 patients were the idiopathic type, 10 heads from 8 patients were the steroidinduced type, and 7 heads from 7 patients were post-traumatic type. All cases received tetracycline preoperatively. Cole's H.E. stain and Villanueva bone stain were done and contact microradiogram was taken from the undecalcified ground sections of the whole-head. Trabecular bone dynamics and pathological findings were investigated by utilizing light and fluorescense microscopy.
In the idiopathic type, empty lacunae in the repaired trabeculae and necrotic debris deposits in the bone marrow space were observed in the necrotic portion. Tetracycline uptake was observed at the trabeculae of the sclerotic band just beneath the demarcation line. These findings suggested good repairing activity in the bone, and that chronic recurrent necrosis existed within the femoral head. In the steroid induced type, generally, there were only a few fibrous tissue formations at the demarcation line and thin bony trabeculae, with little tetracycline uptake. These suggested diminished repairing in new bone formation in this type. In the post-traumatic type, usually wide necrosis was observed with poor repairing, but on the other hand, remarkable repairing was also observed in several cases.
