TREATMENT

RADIOGRAPHIC CHANGES OF CRESCENT SIGN AND COLLAPSE AFTER HIGH DEGREE POSTERIOR ROTATIONAL OSTEOTOMY FOR THE NON-TRAUMATIC OSTEONECROSIS OF THE FEMORAL HEAD

Yasunari Hiranuma, Takashi Atsumi, Satoshi Yoshiwara, Toshihisa Kajiwara
Department of Orthopaedic Surgery, Fujigaoka Hospital, Showa University School of Medicine, Yokohama Japan

42 posterior rotational osteotomies with the non-traumatic osteonecrosis of the femoral head were performed between 1987 and 1999. Of these, 21 hips with a minimum 3 years follow-up (mean, 6 years) were reviewed. All subjects had an extensive lesion outside Sugioka's indications. Rotational angle was ranged from 130 to150 degrees. A mean of the age at the time of surgery was 31 years old. Radiographic changes of crescent sign and collapse moved to the medial area of the head after the rotation were investigated on the follow-up AP radiograph. Crescent sign was noted in 12 of 21 hips at the medial femoral head immediately after operation. 10 of these hips disclosed the disappearance of crescent sign 1 year postoperatively. In 17 of 19 hips had marked collapse at the medial femoral head postoperatively, the form of the femoral head was nearly round final follow-up.