Avascular Necrosis (AVN) Causes, Symptoms & Treatment

Overview

The hip works as a “ball and socket” joint, where the ball at the top of the femur fits into the acetabulum(socket) of the pelvis. Sometimes the femoral head loses its blood supply, and much like a heart attack affecting the heart muscle, the bone begins to die. This is known as Avascular Necrosis (AVN) of the femoral head (or osteonecrosis). About 20,000 new cases are identified each year.

The condition is painful, and without proper treatment, the femoral head may collapse and lead to dysfunction of the  entire hip joint.

What causes Avascular Necrosis (AVN)?

Bones rely on a steady blood supply to remain strong. When circulation to the femoral head is interrupted, the bone weakens and eventually dies. A major hip injury, such as a dislocation or fracture, can trigger AVN by damaging the blood vessels that support the bone.

High-impact collision sports increase the risk of this type of trauma. Other contributing factors include heavy alcohol use, long-term corticosteroid therapy, and certain medical conditions such as sickle cell disease or Crohn’s disease.

• How the Injury Occurs: AVN develops when a significant injury or an internal condition restricts blood flow to the femoral head, causing the bone to deteriorate over time. Without adequate blood supply, the bone tissue collapses, and the hip joint begins to fail.
• Common Everyday Causes: Outside of sports, AVN may result from long-term steroid use, heavy alcohol consumption, or medical conditions that affect circulation. In some cases, a fall, a car accident, or the cumulative effects of certain medications can disrupt blood flow and lead to this condition.Sometimes the cause is never determined.

Sports Where AVN of the Hip Is Most Common:

• Soccer: Hard tackles and sudden collisions can cause traumatic hip injuries.
• Football: High-impact hits increase the likelihood of hip dislocations and fractures.
• Basketball: Intense jumping and fast contact play can stress or injure the hip.
• Rugby: Frequent heavy collisions place athletes at risk for severe hip trauma.

Volleyball: High-energy landings and unexpected falls can affect hip stability.

Symptoms

Avascular Necrosis often develops slowly, and early in the condition, athletes may not notice any changes. As it progresses, hip pain becomes more noticeable, especially during activity. Common symptoms include:

• Constant hip pain that may continue even during rest
• Pain that spreads to the groin, thigh, or buttocks
• Difficulty walking without a limp or shifting weight to the healthy leg
• Stiffness and a reduced range of motion in the hip, which makes bending or turning uncomfortable

Non-operative treatment

When AVN is detected early, conservative treatment can help ease pain and may slow or even stop the condition from progressing. Non-surgical options your doctor may recommend include:

• Rest, to reduce stress on the hip joint
• Using crutches and limiting weight-bearing for up to six weeks to protect the femoral head
• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are used to manage pain and inflammation
• Gentle exercises, such as riding a stationary bike or walking in a pool, to maintain mobility without

Try these exercises to help address your condition:

Below is a PDF of the Exercise Program

Avascular Necrosis

Surgical Treatment

For many patients with AVN, surgery is the most effective option. If the condition is detected early, before the femoral head collapses, certain procedures may help preserve the hip. Core decompression involves drilling into the affected bone to stimulate new blood vessel growth and replace dead bone with healthy tissue. Other options include bone grafts, which use healthy bone from another part of the body or a donor.

When AVN advances and the femoral head collapses, a total hip replacement may be necessary. This procedure removes the damaged joint and replaces it with an artificial ball-and-socket joint.