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.
Avascular necrosis of the bone is a complication of corticosteroid use, trauma, systemic lupus erythematosus, pancreatitis, alcoholism, gout, and sickle cell disease, as well as other diseases.
Patients may present with hip pain or (referred) knee pain. Physical examination will disclose that internal rotation of the hip - not movement of the knee - is painful.
Initially, plain X-rays are often normal. An MRI (Magnetic Resonance Imaging), CT (Computed Tomography) scan, and bone scan are all more sensitive techniques.
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.
