Abstract
Osteonecrosis of the femoral head is usually progressive and once collapse of the femoral head develops, joint destruction almost invariably follows. Therefore, various methods of surgical treatment have been developed in an attempt to save the femoral head and maintain the natural function of the hip joint. We studied the histological findings of the necrotic lesion of cases of osteonecrosis of the femoral head following transtrochanteric anterior rotational osteotomy described by Sugioka and varus osteotomy. We were able to evaluate four hips followings osteotomy. They were all male with average age at operation being 36 years and with age range of 25-52 years. In two patients, osteonecrosis was associated with steroid administration and in he remaining two cases with alcohol abuse. According to the classification of the Japanese Investigation Committee, three hips were stage II and one was stage III. All four hips were obtained following removal of screws from 2 to 4 years postoperatively average of 2.9 years). The specimens were cut to thickness of 5μm and were subjected to hematoxylin and eosin stain and Pas-Alcian blue stain. Histologically, in three cases the preoperative necrotic lesion remained as necrosis without reparative reaction and in one case proliferation of new fibrous connective tissue and blood vessels was observed in the necrotic lesion. Though the number of osteoblasts and osteocytes was decreased, the bone structure was well preserved, indicating that the purpose of femoral osteotomy was achieved. It is necessary in future to study cases with a longer postoperative course by delaying the time of bone biopsy.
