Aseptic bone necrosis, especially osteonecrosis of the femur head, is one of the most disabling complications in patients under long-term corticosteroid therapy after renal transplantation and is an obstacle to rehabilitation. The incidence of aseptic osteonecroses after transplantation is in a high degree variable and its sporadic nature is poorly understood. Aseptic bone necrosis seems clearly related to steroid therapy as its incidence drops with the use of new immunosuppressants such as cyclosporin A.
