Avascular necrosis is the death of bone tissue due to a lack of blood supply. Also called osteonecrosis, it can lead to tiny breaks in the bone and cause the bone to collapse. The process usually takes months to years.
A broken bone or dislocated joint can stop the blood flow to a section of bone. Avascular necrosis is also associated with long-term use of high-dose steroid medications and too much alcohol.
Anyone can be affected. But the condition is most common in people between the ages of 30 and 50.
Some people have no symptoms in the early stages of avascular necrosis. As the condition worsens, affected joints might hurt only when putting weight on them. Eventually, you might feel the pain even when you're lying down.
Pain can be mild or severe. It usually develops gradually. Pain associated with avascular necrosis of the hip might center on the groin, thigh or buttock. Besides the hip, the shoulder, knee, hand and foot can be affected.
Some people develop avascular necrosis on both sides, such as in both hips or in both knees.
Avascular necrosis occurs when blood flow to a bone is interrupted or reduced. Reduced blood supply can be caused by:
Joint or bone trauma
Fatty deposits in blood vessels
Certain diseases
Sometimes the cause of avascular necrosis not brought on by trauma isn't fully understood. Genetics combined with overuse of alcohol, certain medications and other diseases likely play a role.