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Avascular Necrosis AVN
Bone requires a constant blood supply to remain healthy; without it,
bone begins to die and collapse. This is called avascular necrosis,
literally bone death due to lack of blood vessels. In the hip, the head
of the femur (the acetabulum, or "ball") is primarily affected. If not
treated, the joint surface breaks down, leading to arthritis, pain and
disability.
The most common reason why the femoral blood supply is compromised is a
hip fracture that tears the vessels supplying blood to the head of the
femur. Another cause is taking steroid medications, such as prednisone
and other immunosuppressant drugs. AVN is often seen in patients with
chronic asthma, rheumatoid arthritis, lupus and organ transplants.
Avascular necrosis can be diagnosed with x-rays, bone scans and other
imaging methods. To prevent further bone destruction and ensure the
survival of the affected hip joint, there are a variety of treatment
options. Less invasive ones include reduced weight-bearing, medications
and electrical stimulation to increase the growth of new bone and blood
vessels.
Several surgical procedures are also available.
Core decompression, best used in patients with
early-stage disease, removes the inner layer of bone, reducing pressure
and increasing blood flow.
An osteotomy can be done to reshape the bone,
alleviating stress on the affected area. (This comes with a very long
recovery period, however.)
Bone grafts can help support the bone after core
decompression by transplanting some of the patient's healthy bone into
the diseased area.
When the architecture of the hip joint is completely
destroyed due to avascular necrosis, total joint replacement is the
treatment of choice.
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