What're the risk factors for avascular necrosis?Injury: When a joint is injured, as in a fracture or dislocation, the blood vessels may be damaged. This can interfere with the blood circulation to the bone and lead to trauma-related avascular necrosis. Studies suggest that this type of avascular
necrosis may develop in more than 20 percent of people who dislocate their hip joint.
Steroid Medications: Corticosteroids such as prednisone are commonly used to treat diseases in which there is inflammation, such as systemic lupus erythematosus, rheumatoid arthritis, and vasculitis. Studies suggest that long-term, systemic (oral or intravenous) corticosteroid use is associated with 35 percent of all cases of non-traumatic avascular necrosis. However, there is no known risk of avascular necrosis associated with the limited use of steroids. Patients should discuss concerns about steroid use with their doctor. Doctors aren't sure exactly why the use of corticosteroids sometimes lead to avascular necrosis. They may interfere with the body's ability to break down fatty substances. These substances then build up in and clog the blood vessels, causing them to narrow. This reduces the amount of blood that gets to the bone. Some studies suggest that corticosteroid-related avascular necrosis is more severe and more likely to affect both hips (when occurring in the hip) than avascular necrosis resulting from other causes.
Alcohol Use: Excessive alcohol use and corticosteroid use are two of the most common causes of non- traumatic avascular necrosis. In people who drink an excessive amount of alcohol, fatty substances may block blood vessels causing a decreased blood supply to the bones that results in avascular necrosis.
Other Risk Factors: Other risk factors or conditions associated with non-traumatic avascular necrosis include Gaucher's disease, pancreatitis, radiation treatments and chemotherapy, decompression disease, and blood disorders such as sickle cell disease.