Osteonecrosis occurs when bone tissue dies, which can cause the bone to collapse, according to the National Institute of Arthritis and Musculoskeletal Diseases. The condition can affect any bone but is most common in the thigh, upper arm, knees, shoulders and ankles. Symptoms include joint pain, which can be severe, and a loss of mobility in the affected joint. Osteonecrosis is caused by a loss of blood supply to the affected bone.
Medication
One of the most common causes of osteonecrosis is long-term use of high doses of corticosteroids like prednisone, according to NIAMS. These drugs are used to treat many inflammatory diseases like lupus, rheumatoid arthritis and asthma. Some research indicates that corticosteroids cause a more severe form of osteonecrosis, reports NIAMS. Biphosphonate drugs, used to treat osteoporosis, have been linked to a rare form of osteonecrosis that occurs in the jaw, reports NIAMS. The problem seems to occur mostly in people receiving large doses of intravenous biphosphonates to rebuild bones after cancer, according to MayoClinic.com.
Alcohol
People who drink large quantities of alcohol can develop fatty blockages in the blood vessels that can cut off the blood supply to the bone, according to NIAMS. This is a common cause of osteonecrosis. The more alcohol a person drinks each day, the more likely he is to develop osteonecrosis, according to MayoClinic.com.
Injury
When a person breaks, dislocates or injures a joint, the blood vessels in the area may also be injured, according to NIAMS. This can block blood flow to the bone and cause osteonecrosis. Hip dislocation or fracture is a major risk for osteonecrosis. Sometimes osteonecrosis develops because of increased pressure inside the bone that squeezes blood vessels. Researchers do not know what causes the increase in pressure.
Other Risk Factors
Osteonecrosis is associated with a number of medical conditions and treatments that may impair blood supply to the bones, according to NIAMS. These include cancer, diabetes, blood diseases like sickle cell anemia, HIV infection, Legg-Calve-Perthes disease, Gaucher's disease, Caisson disease, gout, vasculitis, osteoarthritis and osteoporosis. Also, radiation therapy, chemotherapy, dialysis, and organ transplants, especially kidney transplants, can cause osteonecrosis.
