Description

Avascular necrosis is the death of bone tissue due to lack of blood supply. Also called "osteonecrosis," it can cause small fractures in the bone and, over time, the collapse of the bone.

If the bone is fractured or if the joint is dislocated, blood flow to a segment of the bone may be interrupted. Avascular necrosis is also associated with prolonged high-dose steroid use and excessive alcohol intake. Anyone can be affected by this disorder, but it is most common in people between 30 and 50 years of age.

Many people do not have symptoms in the early stages of avascular necrosis. As the disease gets worse, you may feel pain in the affected joint only when you support your weight. Over time, you may feel pain even if you are lying down.

Avascular necrosis occurs when blood flow to a bone is interrupted or reduced. Decreased blood supply may be due to the following causes:

• Bone or joint trauma. Injury, such as a dislocated joint, could damage nearby blood vessels. Cancer treatments using radiation can also weaken bones and damage blood vessels.
• Fat deposits in blood vessels. Fat (lipids) can block small blood vessels, reducing the blood flow that nourishes bones.
• Certain diseases. Some diseases, such as sickle cell anemia and Gaucher disease, can also cause reduced blood flow to the bones.

The cause of disruption of blood flow in approximately 25% of people with avascular necrosis is unknown.

To reduce your risk of avascular necrosis and improve your overall health, do the following:

Limit the consumption of alcoholic beverages. Heavy drinking is one of the greatest risks for avascular necrosis. Keep cholesterol levels low. Very small fragments of fat are the most common substances associated with blockages of blood supply to bones. It controls steroid intake. Make sure your doctor knows about high-dose, past, or present steroid use. Steroid-related bone damage appears to worsen with repeated cycles of high-dose steroids. Don't smoke. Smoking increases your risk.