[Clinical condition of steroid-induced osteonecrosis of the femoral head].

Steroid-induced osteonecrosis of the femoral head (steroid-induced ONF) is an aseptic and ischemic disease developing after steroid therapy. Functions of hip joint are markedly disturbed when collapse is developed on the femoral head. Steroid-induced ONF accounted for the majority of the ONF. The occurrence mechanism is unknown, and prevention methods and fundamental remedies remain to be established. The timing of the occurrence of steroid-induced ONF is within several months after steroid administration. During the continuous steroid administration, no expansion of necrotic area was found. Recurrence was not also noticed. Patients have no symptoms when steroid-induced ONF occurs due to the establishment of ischemic conditions, and pain appears when the collapse of femoral head develops. There is an interval of several months or years between the occurrence of ONF and the onset of symptoms. Generally, conservative treatment is chosen during the asymptomatic period, and surgical treatment is considered after the symptoms appear. Appropriate screening and early detection are important to rational remedy for steroid-induced ONF.