Avascular necrosis is the
death of bone tissue due to a lack of blood supply. Also called
osteonecrosis, avascular necrosis can lead to tiny breaks in the bone
and the bone's eventual collapse.
The blood flow to a section of bone can be interrupted if the bone is
fractured or the joint becomes dislocated. Avascular necrosis is also
associated with long-term use of high-dose steroid medications and
excessive alcohol intake.
The most common joint affected by avascular necrosis is the hip.
Avascular necrosis worsens with time, so managing it is a lifelong
Avascular necrosis typically causes pain and reduced range of motion in
the affected joint. The most common joints affected by avascular
* Hip. In addition to pain in the hip joint itself, pain also may
radiate into your groin or go down your thigh to your knee.
* Knee. In avascular necrosis of the knee, the pain occurs most often on the inside of the knee and worsens with activity.
* Shoulder. Several bones come together at the shoulder, but the one
most commonly affected by avascular necrosis is the upper arm bone.
Some people experience avascular necrosis bilaterally — for example, in
both hips or in both knees. Signs and symptoms may appear suddenly if
caused by an injury. In other cases, the pain and stiffness may build up
slowly over several months. Some people with avascular necrosis
experience no symptoms at all.
Other joints that are affected by avascular necrosis include:
When to see a doctor
See your doctor if you experience persistent pain in any joint. Seek
immediate medical attention if you believe you have a broken bone or a
Avascular necrosis occurs when blood flow to a bone is interrupted or reduced, which may be caused by:
* Joint injury. Impacts that result in a broken bone or a dislocated
joint may also damage or destroy nearby blood vessels. Without a steady
supply of oxygen and nutrients, bone cells die.
* Narrowed blood vessels. The blood flow to a bone can be decreased
if the passage through a vessel becomes narrowed or clogged, most
commonly by a tiny bit of fat or — in the case of sickle cell anemia —
by clumps of deformed blood cells.
* Pressure inside the bone. Some medical treatments or conditions,
such as Legg-Calve-Perthes disease or Gaucher's disease, can increase
the pressure inside the bone — making it more difficult for fresh blood
The two most common risk factors of avascular necrosis are:
* Corticosteroids. People who take high doses of corticosteroids,
such as prednisone, for long periods of time — for instance, people with
chronic illnesses such as rheumatoid arthritis and lupus — are more
likely to experience avascular necrosis.
* Heavy drinking. Several alcoholic drinks a day for several years
can cause fatty deposits to form in your blood vessels. This can
restrict the flow of blood to your bones. The more alcoholic drinks you
consume on a daily basis, the higher your risk of avascular necrosis.
Osteoporosis drugs may harm jaw
People who take bisphosphonates — a type of medicine used to help
strengthen bones weakened by osteoporosis — sometimes develop
osteonecrosis of the jaw. This risk is higher for people who have
received high doses of bisphosphonates intravenously to counteract the
damage caused by cancer in the bones.
Procedures can increase risk
Several types of medical procedures can weaken bones, making it easier for you to develop avascular necrosis. Examples include:
* Cancer treatments such as chemotherapy or radiation
* Dialysis, a process to clean the blood after kidney failure
* Kidney and other organ transplants
Conditions linked to bone death
Many underlying medical conditions increase your risk of developing avascular necrosis. They include:
* Gaucher's disease
* Kienbock's disease
* Legg-Calve-Perthes disease
* Sickle cell anemia
Avascular necrosis that goes untreated will continue causing
deterioration of the bone. Eventually the bone may become weakened
enough that it collapses, causing pain and disability. Letting your
avascular necrosis go untreated could lead to severe pain and loss of
movement within two to five years.
Preparing for your appointment
Although you may initially bring your signs and symptoms to the
attention of your family doctor, he or she may refer you to a
rheumatologist — a doctor who specializes in disorders of the joints —
or to an orthopedic surgeon.
What you can do
Before your appointment, you may want to prepare a list that answers the following questions:
* Where exactly does it hurt?
* Does any particular joint position make the pain better or worse?
* How long have you had this pain?
* Have you ever injured this joint in the past?
* What other medical conditions, if any, do you have?
* Are there health problems that tend to run in your family?
* What types of medications and supplements do you take?
What to expect from your doctor
During the exam, your doctor will press around your joint, checking for
tenderness. He or she may also move your joints through a variety of
positions to see if your range of motion has been reduced.
Tests and diagnosis
Many disorders can cause joint pain. Imaging tests can help pinpoint the proper diagnosis.
* X-rays. In the early stages of avascular necrosis, X-rays usually
appear normal. But X-rays can often reveal bone changes that occur in
later stages of the disease.
* Magnetic resonance imaging (MRI). MRI scans can show early changes
in the bone that may indicate avascular necrosis. MRI uses radio waves
and a strong magnetic field to produce detailed images of internal
* Bone scan. For a bone scan, a small amount of radioactive material
is injected into your vein. This material then travels to the parts of
your bones that are injured or healing, and shows up as bright spots on
the imaging plate.
Treatments and drugs
The treatment goal for avascular necrosis is to prevent further bone
loss. What treatment you receive depends on the amount of bone damage
you already have. Early stages of avascular necrosis may benefit from
more conservative treatment, while later stages may require surgery.
* Nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs, such as
aspirin or ibuprofen (Advil, Motrin, others), may help relieve the pain
and inflammation associated with avascular necrosis.
* Bisphosphonates. Some studies indicate that osteoporosis
medications, such as alendronate (Fosamax), may slow the progression of
* Rest. Reducing the amount of weight and stress on your affected
bone may slow the damage of avascular necrosis. You may need to restrict
the amount of physical activity you engage in. In the case of hip or
knee avascular necrosis, you may need to use crutches to keep weight off
your joint for several months.
* Exercises. Certain exercises may help you maintain or improve the
range of motion in your joint. A physical therapist can choose exercises
specifically for your condition and teach you how to do them.
* Electrical stimulation. Electrical currents may encourage your
body to grow new bone to replace the area damaged by avascular necrosis.
Electrical stimulation can be used during surgery and applied directly
to the damaged area. Or it can be administered through electrodes
attached to your skin.
Surgical and other procedures
* Core decompression. In this operation, your surgeon removes part
of the inner layer of your bone. This can relieve pressure within your
bone, reducing your pain. The extra space allows your bone to form new
blood vessels and stimulates the production of new bone.
* Bone transplant (graft). During this procedure, your surgeon takes
healthy bone from another part of your body and implants it into the
area affected by avascular necrosis. Sometimes this is done in
conjunction with core decompression.
* Bone reshaping (osteotomy). This procedure reshapes the bone to
reduce the amount of stress placed on the area affected by avascular
necrosis. Osteotomy is usually used in people with advanced avascular
necrosis. Recovery may take up to a year.
* Joint replacement. If your diseased bone has already collapsed or
other treatment options aren't helping, you may need joint replacement
surgery. Joint replacement surgery replaces your joint with an
artificial one. It requires months of recovery, including time spent
learning to use your new joint.