Avascular necrosis (of bone) is deterioration of bone due to a diminished blood supply.
The reduced blood flow to the bone may be the result of blockage by a blood clot, medication, or the deliberate stoppage of flow during surgery or because of measures taken to control a hemorrhage (major bleed).
The most commonly affected sites are the proximal and distal femoral heads, the upper part of the leg bone that attaches into your hip. Other commonly affected sites include the ankle, shoulder and elbow.
Most often, the section of bone that develops avascular necrosis needs to be replaced. If this develops in the proximal end of the femur, replacement of the head of the femur and the portion of the pelvis into which the hip inserts is necessary.