Avascular Necrosis

Avascular necrosis is a disease that results from the short-term (temporary) or lifelong (permanent) loss of blood supply to the bone. When blood supply is cut off, the bone tissue dies and the bone can collapse. If avascular necrosis happens near a joint, the joint surface may collapse.

This condition may happen in any bone. It most commonly happens in the ends of a long bone. It may affect one bone, several bones at one time, or different bones at different times.

Causes of Avascular Necrosis

Avascular necrosis may be the result of:

• Injury
• Broken bone (fracture)
• Harm to blood vessels
• Long-term use of medicines, such as corticosteroids
• Heavy, long-term use of alcohol
• Certain long-term (chronic) health conditions
• Certain activities such as undersea diving

Risk Factors for Avascular Necrosis 

You are more at risk if any of these apply to you:

• Injury
• Bone surgery
• Steroid use
• Alcohol use
• Blood disorders, such as sickle cell anemia
• Radiation treatments
• Chemotherapy
• Pancreatitis
• Diver's disease or "the bends" (decompression sickness)
• Blood clots easily
• High cholesterol
• Autoimmune disease
• HIV

Symptoms of Avascular Necrosis

The following are the most common symptoms of avascular necrosis. But symptoms occur a bit differently in each person. Symptoms may include:

• Minor early joint pain
• Joint pain gets worse as bone and joint start to collapse
• Limited range of motion because of pain

The symptoms of avascular necrosis may look like other health conditions or bone problems. Always talk with your doctor for a diagnosis. 

Diagnosing Avascular Necrosis

Along with a complete medical history and physical exam, you may have one or more of the following tests:

• X-ray. This test uses energy beams to make images of internal tissues, bones, and organs onto film.
• CT scan. This is an imaging test that uses X-rays and a computer to make detailed images of the body. A CT scan shows details of the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
• MRI. This test uses large magnets, radio waves, and a computer to make detailed images of organs and structures in the body.
• Radionuclide bone scan. This imaging test uses a very small amount of radioactive material. It is injected into the blood to be seen by a scanner. This test shows blood flow to the bone and cell activity in the bone.
• Biopsy. The doctor removes tissue samples with a needle or during surgery. The samples are looked at under a microscope. It’s done to find cancer or other abnormal cells or to remove tissue from the affected bone.
• Functional assessment of bone. These tests often are done during surgery to measure the pressure inside the bone.

Treating Avascular Necrosis

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

The goal of treatment is to improve your ability to use the joint and stop more damage to the bone or joint. Treatments are needed to keep joints from breaking down. They may include:

• Medicines. These are used to control pain.
• Assistive devices. These are used to reduce weight on the bone or joint.
• Core decompression. For this surgery, the inner layer of bone is removed to reduce pressure, increase blood flow, and slow or stop bone and joint destruction.
• Osteotomy. This procedure reshapes the bone and reduces stress on the affected area.
• Bone graft. In this procedure, healthy bone is transplanted from another part of the body into the affected area.
• Joint replacement. This surgery removes and replaces an arthritic or damaged joint with an artificial joint. This may be considered after other treatments have failed to ease pain or disability.

Other treatments may include certain medicines and combination therapies to promote bone growth.