Avascular necrosis (AVN) is also known as osteonecrosis. It is a condition that occurs when the blood supply to bone tissue is cut off. When bone cells and bone marrow cells are starved of their blood supply, they can die. This can lead to mechanical failure (collapse) of the bone.
Any bone tissue can be affected by Avascular Necrosis, but it is most common in the hips. The condition can occur on one side of the body or on both sides.
Avascular Necrosis can be trouble when it occurs near a joint. The bone surrounding the joint can collapse. This can then result in abnormal wear of the joint and premature failure.
Avascular necrosis is a potentially disabling condition. The outcome depends on the location and degree of bone and joint damage.
Excessive alcohol use and prolonged high-dose steroid use are the two greatest atraumatic risk factors for Avascular Necrosis.
Understanding Avascular Necrosis
Pain is the most common symptom of Avascular Necrosis. Often the pain is localized to the area of affected bone. Sometimes pain is the only symptom.
In the early stages of avascular necrosis, pain is usually felt on weight bearing areas. Eventually, pain may occur at any time, even at rest or during the night. It can be very severe.
If the bone damage is in the hip, there may be pain in the groin, the thigh, or the buttock.
Range-of-Motion of Affected Joints
When a nearby joint is significantly damaged, there can also be a limited range of motion. Pain may worsen when the affected joint is used.
Avascular necrosis is diagnosed after a thorough physical examination and a complete clinical history.
The best test to look for Avascular Necrosis is an MRI. The condition can also be diagnosed with a bone scan. Sometimes an X-ray is all that is required to see the bone damage.
A clue that leads physicians to suspect Avascular Necrosis is that their patient is experiencing an amount of pain that is inconsistent with what is seen on x-ray.
Consider an example where a patient is experiencing severe groin pain but an x-ray of the hip is normal. Despite the x-ray result, the pain is intense resulting in difficulty bearing weight and walking. In this instance, Avascular Necrosis should be suspected and an MRI or bone scan should be arranged.
Avascular necrosis is triggered by an interruption of blood supply to the bone. Several things can trigger this, but the exact cause is controversial.
It’s thought that some people may have a genetic predisposition to avascular necrosis. This means that they might have a gene that makes them more susceptible to Avascular Necrosis.
Avascular Necrosis can also result from a trauma to the bone or joint. For example, a person may suffer a fracture, a dislocation or another injury to a joint or bone that can damage the blood vessels in that area. This can cut off blood supply and prevent the injured bone tissue from healing properly. When this happens, a person often continues to feel pain that does not go away.
Causes that are unrelated to trauma called “atraumatic factors” can also lead to Avascular Necrosis.
Prolonged use of high-dose steroids such as prednisone may result in Avascular Necrosis. Prednisone is a drug that is used to treat many diseases. Short-term doses do not pose a big risk, but long-term use of high doses of prednisone has been linked to Avascular Necrosis.
Excessive Alcohol Intake
Excessive alcohol intake is another factor that increases the risk of Avascular Necrosis.
Avascular Necrosis can also affect people who have experienced bone fracture, especially in the hip or wrist.
Avascular Necrosis is a rare condition. It can affect both men and women of any age, but it depends to a large extent on a person’s associated risk factors. Alcoholism is more common in men than women, whereas more women have lupus than men.
Avascular Necrosis is a serious condition that requires urgent care.
If you have Avascular Necrosis or think you may have it, consult your family doctor. Depending on the cause, you may be referred to an orthopedic surgeon, a specialist in the musculoskeletal system (bones, muscles, and tendons).
If the avascular necrosis is associated with an inflammatory disease such as lupus, you may be referred to a rheumatologist, a specialist in arthritis and autoimmune diseases.
If you are diagnosed with this condition, we recommend that you:
- Learn as much as you can about avascular necrosis.
- Attend your doctor’s appointments regularly
- Get your diagnostic tests done as suggested by your doctor
The first step in treating Avascular Necrosis is to determine the extent of the damage to the bone tissue and the nearby joints. This will allow the doctor to know exactly what they are dealing with so they can create a management plan and prevent the condition from progressing.
If the hip is affected, an MRI will help determine how much of the femoral head (the top end of thigh bone) is involved and where the damage is located. It will also allow the doctor to determine the health of the rest of the hip.
The next step usually involves resting the affected bone and joint. This can mean reducing weight bearing activities by using crutches. Bed rest may be needed if the hip is involved.
Medications for Avascular Necrosis
There are no specific medications that have been shown to be effective for treating Avascular Necrosis or for slowing the progression of the condition.
Some studies suggest that a class of drugs called bisphosphonates may help, but their efficacy has not been established for certain.
Analgesics and NSAIDs
Medications are usually targeted at relieving the pain of Avascular Necrosis. Non-prescription analgesic medications such as acetaminophen (Tylenol) or Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can help control pain. These can be effective at relieving pain, however, they do not prevent further bone damage.
When non-prescription analgesics and NSAIDs are not enough to control pain, stronger medicines called opioids may be used. These should be discussed with your doctor.
While opioids can be very effective at controlling pain, they should be used with caution. These drugs can cause dependence and have been associated with drug abuse.
Examples of opioids include codeine, morphine, and oxycodone.
Reducing Dose of Steroids
If Avascular Necrosis is associated with prolonged steroid use, it is important to taper (reduce) the dose if possible. You should discuss this with your doctor.
Calcium and Vitamin D Supplements
Adequate intake of calcium and vitamin D is important no matter what your fracture risk. A supplement might be required to help you obtain adequate intakes. If you have had a prior fracture, then treatment with medication will likely be required.
Surgery for Avascular Necrosis
Surgery may eventually be needed if Avascular Necrosis continues to progress. In severe cases, the bone and surrounding joint may be badly damaged and lose its ability to function. When that happens, surgery may be necessary to restore a person’s mobility and quality of life.
There are many approaches to surgery. The most effective approach depends on the location and extent of the damage. One strategy is to revascularize the damaged bone tissue. “Revascularize” means to return the blood supply to the damaged tissue. Another approach may to replace a damaged joint with an artificial joint. Hip replacement can help people with severe Avascular Necrosis by reducing pain, improving mobility and restoring their functioning. You should talk to your doctor to find out if surgery is right for you.
Exercise and Avascular Necrosis
While rest is important for patients with Avascular Necrosis, some physical activity may be beneficial. After surgery, exercise can be an important part of rehabilitation. A trained physiotherapist can help design an exercise program tailored to you and your needs. An occupational therapist can help you learn how to protect your body and joints.