Selective reduction of bone blood flow by short-term treatment with high-dose methylprednisolone - An experimental study in pigs

Treatment with corticosteroids is a risk factor for non-traumatic avascular necrosis of the femoral head, but the pathological mechanism is poorly und erstood, Short-term treatment with high doses of methylprednisolone is used in severe neurotrauma and after kidney and heart transplantation. We inves tigated the effect of such treatment on the pattern of perfusion of the fem oral head and of bone in general in the pig, We allocated 15 immature pigs to treatment with high-dose methylprednisolon e (20 mg/kg per day intramuscularly for three days, followed by 10 mg/kg in tramuscularly for a further II days) and 15 to a control group. Perfusion o f the systematically subdivided femoral head, proximal femur, acetabulum, h umerus, and soft tissues was determined by the microsphere technique, Blood flow in bone was severely reduced in the steroid-treated group. The reduct ion of flow affected all the segments and the entire epiphysis of the femor al head. No changes in flow were found in non-osseous tissue, Short-term tr eatment with high-dose methylprednisolone causes reduction of osseous blood flow which may be the pathogenetic Factor in the early stage of steroid-in duced osteonecrosis.