Avascular Necrosis (AVN)

A loss of blood supply to the hip bone leading to joint collapse and chronic pain

Avascular necrosis (AVN), also known as osteonecrosis, is a serious condition that occurs when the blood supply to a section of bone is disrupted. In the hip, this typically affects the femoral head, the ball-shaped part of the thigh bone that fits into the hip socket. Without adequate blood flow, the bone tissue begins to die, which can cause the femoral head to weaken, flatten, and eventually collapse.
AVN can develop gradually or progress rapidly, and often leads to hip pain, stiffness, and difficulty with walking or bearing weight. Over time, it may result in advanced arthritis of the hip joint.

A range of factors may contribute to AVN, including previous trauma (such as a hip fracture or dislocation), long-term use of corticosteroids, excessive alcohol intake, or certain medical conditions. However, in some cases, the cause may be unknown (idiopathic).
Early diagnosis is key, as some cases may be managed with non-surgical treatment if caught in the early stages. For advanced or progressive cases, surgery including total hip replacement may be recommended to restore function and relieve pain.

This page explains the causes, symptoms, diagnosis, and treatment options for AVN of the hip to help you better understand your condition and the pathways available for care.

Around 2.1 million Australians (1 in 11 people) have osteoarthritis, with a 58% increase expected by 2032 due to population ageing and rising obesity rates

What is avascular necrosis (AVN) of the hip?

Avascular necrosis (AVN), also known as osteonecrosis, is a condition that occurs when the blood supply to the femoral head (the ball of the hip joint) becomes disrupted. Without adequate blood flow, the bone tissue begins to die, leading to the collapse of the femoral head, joint deterioration, and eventually, arthritis.

The hip is the most commonly affected joint in AVN, although other joints such as the shoulder or knee may also be involved.
Early diagnosis and treatment are important, as progression of the disease can lead to permanent damage requiring joint replacement surgery.

What causes AVN?

Avascular necrosis can result from a number of underlying causes that reduce blood flow to the femoral head. These may include:

Trauma or fracture of the hip (particularly femoral neck fractures)
Long-term corticosteroid use
Excessive alcohol consumption
Medical conditions such as sickle cell disease, lupus, or blood clotting disorders
Radiation therapy
Decompression sickness (seen in divers or high-altitude pilots)
Certain medications or chemotherapy agents

In some cases, no clear cause can be identified — this is referred to as idiopathic AVN.

Who is at risk of developing AVN?

Avascular necrosis can affect both men and women, typically between the ages of 20 and 60. Risk factors include:

Prior hip trauma or dislocation
Prolonged or high-dose corticosteroid therapy
Excessive alcohol intake
Underlying autoimmune, blood, or metabolic disorders
Family history of AVN or vascular disease
History of cancer treatment or organ transplant

AVN may affect one or both hips. When both sides are involved, this is referred to as bilateral AVN.

Common symptoms of hip AVN

AVN may not cause symptoms in its earliest stages. As the condition progresses and bone tissue begins to break down, symptoms can include:

Pain in the groin, buttock, or thigh
Pain that worsens with walking or standing
Limping or altered gait
Stiffness and reduced hip movement
Pain at rest or during the night (in advanced cases)
Difficulty performing daily activities such as putting on socks or bending forward

In later stages, the femoral head may collapse, leading to joint damage and early-onset osteoarthritis.

How is AVN diagnosed?

Diagnosing AVN typically involves a combination of clinical assessment and imaging. Dr Jason Hockings will begin by reviewing your symptoms, medical history, and any relevant risk factors. Investigations may include:

Investigations may include:

X-rays: Useful for identifying late-stage AVN or femoral head collapse
MRI: The most sensitive test for detecting early AVN before changes appear on X-ray
CT scan: Occasionally used to assess bone structure and plan surgery
Bone scans: May be used in selected cases

The stage and severity of AVN will help determine the most appropriate treatment approach.

Non-surgical treatment options

Non-surgical management may be considered in early-stage AVN when the femoral head is still intact.

Non-surgical strategies may include:

Activity modification to reduce weight-bearing on the hip
Use of crutches or walking aids to offload the joint
Medications to manage pain and inflammation
Bisphosphonates or other bone-targeting agents (in selected cases)
Monitoring with repeat imaging

Non-surgical treatment aims to preserve the joint and delay the need for surgery, but may not be effective once structural collapse begins.

When might surgery be required?

Surgical treatment may be recommended if:

AVN has progressed beyond the early stages
There is evidence of femoral head collapse
Pain is persistent despite conservative measures
Daily activities are significantly impacted
Imaging shows joint surface damage

The type of surgery recommended will depend on the severity of AVN and the condition of the joint.

Surgical treatment for AVN of the hip

Dr Jason Hockings offers a range of surgical procedures for patients with AVN of the hip:

1. Total hip replacement

If the joint is already damaged or the femoral head has collapsed, total hip replacement is often the most reliable treatment. The damaged bone and cartilage are replaced with a prosthetic implant, relieving pain and restoring function.

2. Hip resurfacing surgery

In select younger patients with preserved bone structure and minimal arthritis, hip resurfacing may be considered. This technique preserves more of the native bone compared to total replacement.
Not all patients are suitable for hip resurfacing and careful evaluation is required.

If you have hip pain, have been diagnosed with avascular necrosis, or are concerned about joint deterioration, Dr Jason Hockings can provide a comprehensive assessment and discuss personalised treatment options. Please contact the clinic to book your consultation and take the next step in preserving your hip health.

If you’re living with hip pain or stiffness that’s affecting your quality of life, a thorough assessment can help determine the cause and guide the right treatment path.