Avascular Necrosis (AVN) of the Hip — Diagnosis, Stages & Treatment
Core Takeaway: Avascular necrosis (AVN) is the death of bone tissue in the femoral head due to interrupted blood supply. It commonly affects younger patients (30s–50s) and leads to hip joint collapse if untreated.
- Frequently triggered by alcohol use, idiopathic causes, prolonged steroid intake, or trauma.
- Progresses through four stages. Early stages (1 & 2) require MRI for diagnosis, as X-rays can miss early changes.
- Early treatment focuses on joint preservation (core decompression or bone grafting).
- Advanced Stage 4 AVN requires total hip replacement. High-longevity ceramic implants can last 25–40 years for younger patients.
What is avascular necrosis?
Avascular necrosis — also called osteonecrosis or AVN — is a condition in which the blood supply to the femoral head (the ball of the hip joint) is interrupted. Without blood supply, the bone cells begin to die. The femoral head, deprived of its structural integrity, eventually collapses — destroying the hip joint in the process.
What makes AVN particularly challenging is that it often affects younger patients — people in their 30s, 40s, and 50s — who are active, working, and have decades of life ahead of them. It is not the arthritis of old age. It is a condition that can devastate a young person's mobility if not recognised and treated at the right time.
What causes AVN — and what I see most commonly in Punjab
The causes of AVN are varied, and in my practice at NHS Hospital Jalandhar the two most common patterns I see are:
1. Alcohol consumption
Heavy or prolonged alcohol use is one of the most common causes of AVN in younger male patients in Punjab. Alcohol disrupts fat metabolism in a way that causes fat emboli to block the small blood vessels supplying the femoral head. The damage is cumulative and often silent until the bone begins to collapse. By the time pain appears, the process has usually been ongoing for months or years.
2. Idiopathic AVN — no identifiable cause
In a significant proportion of my patients, no clear cause can be identified. This is called idiopathic AVN. These patients often present confused and frightened — they have not taken steroids, they do not drink heavily, they have no obvious risk factors. The honest answer is that we do not always know why the blood supply fails. What matters is that we identify it, stage it correctly, and treat it appropriately.
Other causes
- Prolonged steroid use: For asthma, autoimmune conditions, or post-transplant patients.
- Post-traumatic: Following hip fracture or dislocation.
- Sickle cell disease.
- Radiation therapy.
What are the stages of AVN?
AVN is classified into stages based on how far the disease has progressed:
- Stage 1: Blood supply is disrupted but the femoral head looks normal on X-ray. MRI is required for diagnosis at this stage.
- Stage 2: Changes visible on X-ray. The femoral head is still round and intact but showing early structural changes.
- Stage 3: The femoral head begins to collapse. A crescent sign appears on X-ray — a thin line beneath the joint surface indicating subchondral fracture.
- Stage 4: Significant femoral head collapse. The joint space narrows. Arthritis sets in. The damage is irreversible.
The stage at diagnosis determines the treatment options available. This is why early presentation — even in the absence of significant pain — is critical in patients with known risk factors for AVN.
How is AVN treated?
Early stages — joint preservation
In Stages 1 and 2, where the femoral head is still intact, joint preservation procedures may be attempted:
- Core decompression: Drilling into the femoral head to relieve pressure and stimulate new blood vessel growth.
- Bone grafting: Replacing dead bone with healthy bone to support the femoral head structure.
These procedures are most successful in early-stage disease in younger patients. Results are variable and not all patients respond — but they offer a chance to delay or avoid hip replacement in carefully selected cases.
Stage 4 — hip replacement
By Stage 4, when the femoral head has collapsed significantly and arthritis has set in, hip replacement is the definitive treatment. There is no joint preservation option that can reverse established collapse and secondary arthritis.
At NHS Hospital Jalandhar, I perform robotic hip replacement for AVN patients using the CORI Surgical System. For younger AVN patients — and I have operated on patients as young as 18 years old for this condition — I use ceramic-on-ceramic implants, which offer the longest implant longevity of any bearing surface available today. With modern ceramic implants, realistic longevity of 25–40 years is expected — meaning many young AVN patients can expect their replacement to last a lifetime.
What should I do if I think I have AVN?
If you have any of the risk factors mentioned above — alcohol use, steroid use, previous hip injury — and you are experiencing groin or hip pain, seek assessment without delay. Do not wait for the pain to become severe. By the time pain is severe in AVN, the femoral head has often already collapsed.
An MRI of the hip is the investigation of choice for early diagnosis. If you have had an X-ray that was reported as normal but pain persists, ask for an MRI specifically.
Book an Evaluation for Hip AVN
Get a correct diagnosis and clear guidance from Dr. Shubhang Aggarwal.
WhatsApp Your X-Rays Call +91 98142 09405 Book AppointmentFrequently Asked Questions
What is avascular necrosis (AVN)?
Avascular necrosis — also called osteonecrosis or AVN — is a condition in which the blood supply to the femoral head (the ball of the hip joint) is interrupted. Without blood supply, the bone cells begin to die, leading to eventual collapse of the femoral head and destruction of the hip joint.
What causes AVN of the hip?
Common causes include heavy or prolonged alcohol use, idiopathic (unknown) factors, prolonged steroid use, trauma (hip fracture or dislocation), sickle cell disease, and radiation therapy.
What are the stages of AVN?
AVN is staged from 1 to 4: Stage 1 (normal X-ray, diagnosed via MRI), Stage 2 (structural changes visible on X-ray, head remains round), Stage 3 (femoral head starts to collapse, crescent sign visible), and Stage 4 (significant collapse, joint space narrowing, and secondary arthritis).
How is AVN treated in the early stages?
In Stages 1 and 2, joint preservation procedures like core decompression (drilling to relieve pressure and promote blood flow) or bone grafting may be attempted to delay or avoid hip replacement.
What is the treatment for advanced Stage 4 AVN?
Stage 4 AVN requires total hip replacement. Dr. Shubhang Aggarwal performs robotic-assisted total hip replacement using ceramic-on-ceramic implants, which offer 25–40 years of longevity, ideal for younger AVN patients.
What should I do if I suspect I have AVN?
If you have risk factors (alcohol, steroids, hip trauma) and feel groin/hip pain, seek medical assessment immediately. A hip MRI is essential, as standard X-rays can appear normal in the early stages.
Correct diagnosis | Clear guidance | Right decision