Avascular necrosis is death of bone tissue due to a lack of blood supply. This can lead to tiny breaks in the bone and the bone's eventual collapse. Avascular necrosis most often affects the head of the thighbone (femur), causing hip pain. But it may affect other bones as well.

Blood supply to the bone can be impaired for a number of reasons, including injuries. Avascular necrosis is also associated with long-term use of steroid medications and excessive alcohol intake. Your doctor might use other terms to describe avascular necrosis, such as osteonecrosis, aseptic necrosis or ischemic bone necrosis.

Avascular necrosis is progressive, meaning it worsens with time. Managing the condition is a lifelong process.