Osteonecrosis is a disease caused by reduced blood flow to the bones. In healthy people, new bone is constantly growing to replace old bone. In people affected by osteonecrosis, new bone is not able to grow and replace old bones because of the reduced blood supply. This leads to a reduction in the amount of bone, which causes pain and limits mobility in joints. Osteonecrosis can affect anyone, but people who are between age 30-50 are most often affected.
The cause of osteonecrosis is reduced blood flow, but the cause of the reduction in blood flow is not always known. Some common causes include alcohol use, steroid medications, injury, and increased pressure in the bones. Major risk factors for osteonecrosis include having undergone chemotherapy and radiation treatments and having had an organ transplant. Certain diseases, such as cancer, lupus, HIV, and many others, also increase the risk for osteonecrosis. Others will develop osteonecrosis due to unknown causes, even without these risk factors.
The symptoms of osteonecrosis are joint pain and, depending on the severity, inability to use a joint. The disease may show no symptoms at all in the early stages, and worsening pain will result as the disease progresses. Treatment is usually based around maintaining function of the affected joints. Without any treatment, the disease will cause progressive loss of mobility. Seeking treatment as soon as possible is important to maintain joint function. Research is currently being done to learn more about the disease. Support groups are also available for more resources and information.