Bilateral osteonecrosis of the femoral head after pregnancy

Published cases of non-traumatic avascular necrosis of the femoral head associated with pregnacy are rare. We report a case of a 41-year-old woman who suddenly complained of bilateral hip pain 3 weeks after delivery by Caesarean section. For a problem of sterility, she had been treated with human menopausal gonadotropin and human chorionic gonadotropin (hMG-hCG). Initial radiographs of both hip joints were considered regular. After 4 years evolution, radiographs of the hip joint showed collapse of both femoral heads. Bilaterally, osteonecrosis of the femoral heads was confirmed by MRI. MRI revealed a band pattern of low signal intensity for both hips on T1- and T2-weighted images. She had no history of steroid therapy or alcohol abuse. Osteonecrosis was related to pretentaine. A bilateral total hip arthroplasty was performed. The literature about avascular necrosis of the femoral head associated with pregnacy in previous cases is reviewed.