What causes avascular necrosis?

What causes avascular necrosis?

Bone fractures or disease that prevent blood flow to bone tissue causes avascular necrosis. About 20% of avascular necrosis cases happen without an obvious cause.

Known causes of avascular necrosis are:

• Traumatic avascular necrosis: This can happen after you break a bone or dislocate a joint.
• Nontraumatic avascular necrosis: This happens if you have an illness or medical condition that keeps blood from flowing to your bone tissue. Nontraumatic avascular necrosis often affects the same bones on both sides of the body. For example, if you have avascular necrosis in your right shoulder, you're likely to have it in your left shoulder.