Avascular necrosis, also known as osteonecrosis, AVN or bone necrosis, is a condition where a reduced blood supply causes small areas of your bone tissue to deteriorate over time. It most commonly affects your hip, but it can also occur in your knee, shoulder, ankle and other joints. Early diagnosis and treatment are important, as they can help slow progression, reduce pain and protect long-term joint function.
If you’re experiencing joint pain or stiffness and are concerned about AVN, you can book an appointment with a Ramsay specialist for a prompt assessment.
What is avascular necrosis?
Healthy bone relies on a steady, reliable blood supply. When that blood flow is reduced or interrupted, the affected bone tissue can no longer receive the oxygen and nutrients it needs, and the bone cells begin to die. This process is known as avascular necrosis, and you may also hear it called osteonecrosis, AVN or bone necrosis, all terms refer to the same condition.
Without treatment, the weakened bone may gradually lose its normal structure, collapse or change shape, which can lead to joint damage and arthritis. AVN most often affects the femoral head at your hip, but it can also occur in your knee, shoulder, ankle, wrist and foot. It can affect people of any age, though it is most diagnosed between 30 and 60.
The reassuring news is that with prompt diagnosis and appropriate treatment, many patients maintain good joint function and slow or prevent further deterioration. For hip-related AVN, you can read more about your joint treatment options on our hip replacement page.
If you’re concerned about symptoms or want specialist advice, you can book an appointment with one of our Ramsay orthopaedic consultants.
Avascular necrosis symptoms
Symptoms of AVN can be subtle at first. In the early stages, some people have no symptoms at all, and the condition is sometimes found incidentally on X-rays or MRI scans performed for another reason.
As AVN progresses, symptoms typically develop gradually over weeks to months and may include:
- Joint pain - often felt when bearing weight or moving the affected joint. It is later present even at rest
- Pain in surrounding areas - such as your groin, thigh or buttock for hip AVN, or your shoulder, knee or ankle depending on which joint is affected
- Stiffness and reduced range of motion
- Limping if your hip or knee is affected
- Difficulty with everyday activities, including walking, climbing stairs or reaching overhead
Persistent joint pain that doesn’t ease with rest or simple over-the-counter pain relief should be checked by a healthcare professional. Getting assessed early helps identify what’s going on and gives you the best chance of slowing any progression and protecting long-term joint function.
Avascular necrosis causes and risk factors
Avascular necrosis (AVN) can develop when your blood supply to a bone is disrupted. This may happen after an injury, or due to medical or lifestyle factors that affect blood flow. In some cases, no clear cause is found.
Traumatic causes
- Hip fracture or dislocation – is the most common traumatic cause. These injuries can damage the blood vessels that supply your femoral head
- Wrist fractures, particularly scaphoid fractures, which can interrupt blood flow to the small bones of your wrist
Non-traumatic causes
- Long-term or high-dose corticosteroid use (such as prednisone) - a leading non-traumatic cause. Steroids may raise your blood lipid levels, reducing blood flow to your bone
- Excessive alcohol consumption - can lead to fatty deposits in your blood vessels
- Blood disorders, including sickle cell anaemia, lupus, and antiphospholipid syndrome
- Decompression sickness, more common in divers
- Cancer treatment, particularly radiation therapy, which can weaken your bone and blood vessels
- Organ transplantation medications (immunosuppressants)
- Other medical conditions, including pancreatitis, Gaucher disease, and HIV
- Idiopathic AVN - in some cases, no clear cause is identified
Risk factors
Factors that increase the likelihood of developing AVN include:
- Steroid use - the most significant modifiable risk factor
- Heavy alcohol use
- Smoking - as it narrows blood vessels and reduces blood flow
- High cholesterol - can contribute to fatty deposits in blood vessels
- Underlying medical conditions listed above
- Previous joint injury or surgery which may affect blood supply
Stages of avascular necrosis
Avascular necrosis (AVN) progresses through four stages. Changes may be subtle at first and become more noticeable as the condition advances.
1. Stage 1
X-rays usually appear normal, but an MRI can detect early bone changes. Patients may have no symptoms or only mild, occasional pain.
2. Stage 2
Structural changes become visible on an X-ray. The affected bone begins to show early damage, and pain typically increases, but there is no collapse yet.
3. Stage 3
A characteristic crescent sign appears on imaging, showing that the bone is starting to collapse beneath the joint surface. Pain and stiffness become more significant.
4. Stage 4
The joint surface collapses, leading to severe arthritis and a marked loss of function. Pain is often persistent and may limit daily activities.
Progression varies greatly between individuals, and not everyone reaches stage 4. Early diagnosis at stages 1 to 2 offers the best chance of slowing progression and protecting long-term joint function.
How is avascular necrosis diagnosed?
Diagnosis of AVN begins with a consultation with an orthopaedic specialist. Your clinician will take a detailed medical history, examine your affected joint, and assess your range of motion, strength and areas of tenderness. If AVN is suspected, imaging is essential to confirm your diagnosis and determine the stage of your condition.
Imaging tests
- X-ray - can identify bone changes from stage 2 onwards, but may appear normal in the early stages of AVN. An X-ray is useful for assessing bone shape, joint alignment and signs of collapse.
- MRI - is the gold standard for early diagnosis. MRI can detect AVN before X-ray changes appear, showing reduced blood flow and early bone damage. It also helps identify how much of the bone is affected.
- CT scan - provides highly detailed images of bone structure and is particularly helpful when assessing the extent of collapse or planning surgical treatment.
- Bone scan - is occasionally used to assess blood flow and bone activity, though less commonly required when MRI is available.
Ramsay offers fast access to on-site MRI, CT and X-ray, with same-day or next-day imaging often available across our UK hospitals. This means you can move quickly from consultation to diagnosis and begin treatment without delay.
If you’re experiencing persistent joint pain or stiffness, you can book a consultation with a Ramsay orthopaedic specialist.
Avascular necrosis treatment
Treatment depends on your stage of AVN, which joint is affected, and whether bone collapse has occurred. The goal is to preserve your joint where possible. If collapse has already happened, the focus shifts to restoring function.
Non-surgical treatment for avascular necrosis
- Activity modification and rest - reducing weight-bearing on your affected joint can help slow progression. Walking aids may be recommended to reduce pressure on your hip, knee or ankle.
- Pain management - anti-inflammatory medicines (NSAIDs) may help manage discomfort and inflammation. These do not treat AVN itself but can improve day-to-day comfort.
- Medications to improve blood flow - in certain clotting disorders, anticoagulants may be used to support blood flow to your affected bone.
- Cholesterol-lowering medication - if high lipid levels are contributing to reduced blood flow, cholesterol-lowering treatment may be considered.
- Extracorporeal shockwave therapy (ESWT) - an emerging non-invasive option for early-stage AVN. ESWT uses targeted shockwaves to stimulate bone healing.
- Physiotherapy – strengthens the surrounding muscles can help support your joint, improve mobility and reduce load on your affected area.
Surgical treatment for avascular necrosis
Core decompression
Core depression is the most common surgical option for early‑stage AVN (stages 1–2). A small channel is drilled into your affected bone to relieve pressure and encourage new blood vessel growth. It is often combined with bone grafting and has the best outcomes before bone collapse.
Bone grafting
Healthy bone tissue (from the patient or a donor) is used to support or replace damaged bone. This may be combined with core decompression to improve stability and healing.
Osteotomy
Your affected bone is reshaped or repositioned to shift weight away from the damaged area. This option is used when collapse is limited and your joint surface can still be preserved.
Joint replacement (arthroplasty)
Recommended when your joint surface has collapsed and joint‑preserving surgery is no longer viable. Hip or knee replacement can be highly effective at restoring your mobility and eliminating pain.
Learn more about hip replacement and knee replacement
How long can you live with avascular necrosis?
Avascular necrosis is not a life-threatening condition and does not affect your life expectancy. The main impact is on quality of your life, particularly your mobility, comfort and joint function.
Without treatment, AVN typically progresses over months to years, and your affected bone may eventually collapse. With appropriate treatment, many patients maintain good joint function for a long time, especially when AVN is diagnosed and managed in the early stages.
Outcomes vary between individuals and depend on several factors, including:
- the stage at diagnosis
- which joint is affected
- the underlying cause
- how quickly treatment begins
Early-stage AVN treated before bone collapse carries a much better prognosis than late-stage disease. For patients who develop severe joint collapse, joint replacement surgery is often recommended and is highly effective at restoring mobility and reducing pain.
Your orthopaedic surgeon will discuss the likely progression of AVN and the most suitable treatment options based on your individual circumstances.
Avascular necrosis treatment at Ramsay Health Care
Ramsay Health Care provides expert, patient-centred care for avascular necrosis (AVN). We offer fast access to diagnosis, joint-preserving treatments and advanced surgical options when needed. Our hospitals across the UK deliver high-quality orthopaedic care with shorter waiting times than the NHS.
Why choose Ramsay for your AVN care?
- Experienced orthopaedic consultants specialising in bone and joint conditions, including early-stage and advanced AVN
- Fast access to diagnostic imaging, with on-site MRI, CT and X-ray available at hospitals across the UK
- Shorter waiting times for both consultation and surgery compared with the NHS
- Full spectrum of care, from conservative management through to joint-preserving surgery and joint replacement
- Physiotherapy support to aid recovery and improve long-term joint function
- Self-pay options, including the Total Care package and 0% payment plans. We also accept most major private medical insurance.
Book an appointment online or call 0808 223 0500
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