Avascular Necrosis Hip Joint (AVN)

What avascular necrosis of the hip is

The hip is a ball and socket joint. The ball, the head of the femur, is covered in smooth cartilage where it meets the socket in the pelvis. Like all bone it depends on a blood supply, and the vessels reaching the femoral head follow a relatively narrow route. If that supply is reduced or interrupted, bone cells in the affected area can die.

What happens next varies. In some cases the involved area is small and the bone remains structurally sound. In others the weakened bone beneath the cartilage loses its support, and the normally round contour of the femoral head may flatten or collapse. Once the shape of the ball changes it no longer matches the socket, and the cartilage on both sides can wear, producing arthritis. Circumstances associated with AVN include previous hip fracture or dislocation, longer term use of certain medications, heavy alcohol use, sickle cell disease and radiation treatment, and sometimes no associated factor is identified. An association is not the same as a cause, and diagnosis requires examination and imaging.

Symptoms that often bring people in

• Pain felt in the groin, sometimes spreading to the buttock, thigh or knee
• Pain that is worse with standing, walking or putting weight through the leg
• Aching that continues at rest or interferes with sleep
• Stiffness, or difficulty putting on shoes and socks
• A limp, or the leg feeling unreliable
• Symptoms in both hips, since AVN can affect more than one joint

How it is evaluated

Assessment begins with a history, including any injury to the hip, medications and other medical conditions, followed by examination of hip range of motion, gait and the pattern of pain. X-rays are usually obtained first, though early changes may not be visible, and a normal X-ray does not by itself settle the question. MRI is often used because it can show changes in the bone marrow before the shape of the head has altered. Because groin and hip pain have many possible sources, part of the evaluation is distinguishing AVN from other conditions.

Treatment options in general terms

Treatment depends on how much of the femoral head is involved, whether its shape has changed, and on your symptoms, age and general health.

• Activity and load modification. Adjusting activities, and sometimes using a cane, may be advised to reduce load through the joint.
• Monitoring with repeat imaging. Following the hip over time helps establish whether the affected area is stable or progressing.
• Managing associated conditions. Where an underlying medical factor is identified, treatment is directed by the physicians managing it.

Surgical options fall into two groups: procedures intended to preserve the natural hip, generally considered before the head has collapsed, and joint replacement, considered when the joint surface has been lost.

• Core decompression. Channels are made into the affected area of the femoral head with the aim of reducing pressure and encouraging new blood vessel formation.
• Bone grafting and osteotomy. Grafting can add structural support, and in selected cases the bone may be repositioned to shift load away from the affected part.
• Hip replacement. Where the femoral head has collapsed or arthritis has developed, replacing the joint surfaces may be discussed. Dr. Wolfson performs hip replacement using the direct anterior approach.

What to expect when you consult Dr. Wolfson

Dr. Wolfson is board certified in the United States and Canada, and his practice covers both joint preserving surgery and hip replacement, which matters in AVN because the reasonable options change as the condition evolves. A consultation typically includes reviewing your imaging, discussing where your hip sits in that progression, and setting out what each option would involve.

This page provides general information about avascular necrosis of the hip and is not medical advice. It is not a substitute for examination, imaging and diagnosis by a qualified physician. Every case is different and requires individual evaluation. If you have severe pain, an obvious deformity, loss of function, fever, or an injury from a significant accident, seek medical care promptly.

Contact Dr. Wolfson if you would like to setup an appointment. If you are a new patient, please book all in-person appointments with Dr. Wolfson via telephone.

If you live outside of the San Francisco Bay Area, you can request a complimentary phone consultation with Dr. Wolfson to assess your case. Please call or e-mail us to set up your complimentary consultation.

Call: (415) 221-4400

E-mail: [email protected]