Avascular Necrosis

Avascular necrosis (or osteonecrosis) involves bone death due to a loss of blood supply to the affected bone. The most commonly affected bones are the talus, the hip, and the femur. It most often occurs in bones that do not have good access to a blood supply. Localized cases can be caused by a fracture or other trauma to the affected bone. Non-traumatic avascular necrosis that affects more than one bone can be caused by such things as longterm steroid use, radiation treatment, or alcoholism. It is estimated that more than 30% of non-traumatic cases are caused by steroid use.