What is avascular necrosis?

In adolescents and young adults with avascular necrosis (AVN), the blood supply to the hip joint is interrupted and the bone begins to die. Also called osteonecrosis, AVN can lead to tiny breaks in the bone and eventual collapse of the ball of the hip joint (femoral head). Although no one knows exactly why AVN occurs, we do know that it is often associated with several underlying conditions such as previous chemotherapy, steroid use, sickle cell disease among others.

Symptoms

AVN can cause pain in the hip, thigh or knee. The hip joint usually becomes stiffer, and pain can either start abruptly or build over weeks or months.

Diagnosis

A diagnosis of AVN may be suspected after a detailed history and physical examination, and x-rays may be sufficient to confirm the diagnosis. In cases of early AVN, however, x-rays may not show the condition and further imaging may be necessary.

Advanced Imaging helps our doctors better understand what’s going on deep inside your hip socket. We may recommend specialized advanced imaging studies, which are all available at CHOP:

• Perfusion MRI — MRI technique which evaluates blood flow to the bone looking for areas of AVN.
• Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) — imaging where an MRI scan is dedicated to detecting early cartilage breakdown and allows mapping of areas of early osteoarthritis or focal cartilage injury

Treatment

Non-surgical treatments

When treating hip pain, non-surgical treatments should always be considered first. In some cases, conservative treatments such as rest, activity restriction, physical therapy, and/or pain medication can resolve the pain and swelling.

Surgical treatment

If the hip pain or discomfort caused by avascular necrosis does not improve with non-operative treatment, or if your doctor is concerned about further collapse of the ball and worsening of your condition, surgery for AVN may be recommended.