- M.B.B.S.
- M.S. Orthopaedics
- Fellow in Knee and Hip Replacement, Mumbai
- Fellow In Knee and Hip Surgery, Germany
- Fellow in Knee and Hip Surgery, NHS, Singapore
- Fellowship in Complex and revesion knee and Hip replacement, London, Lancaster, UK
Avascular necrosis of the hip commonly abbreviated as AVN or sometimes called osteonecrosis is a condition where the bone in the femoral head (the ball at the top of the thigh bone) loses its blood supply, dies, and progressively collapses. It’s a serious diagnosis, but with one critical fact most patients aren’t told clearly enough:
early-stage AVN can often be treated without joint replacement, but late-stage AVN almost always cannot.
Timing is everything. This post explains what AVN is, how to recognise it early, the realistic treatment options at each stage, and why patients who get diagnosed and treated within the first 6-12 months have dramatically different outcomes than those who delay.
What Causes AVN of the Hip?
AVN happens when blood supply to the femoral head is interrupted. The bone tissue dies (necrosis), loses structural strength, and eventually collapses under body weight.
Causes include:
• Prolonged steroid use – by far the most common cause in India today. High-dose oral steroids (often used for asthma, autoimmune disease, organ transplant, severe COVID-19 treatment, or unfortunately by patients self-medicating chronic pain conditions) damage the small blood vessels supplying the femoral head.
• Heavy alcohol use – chronic alcohol consumption alters bone metabolism and vascular supply.
• Trauma – hip fractures or dislocations can disrupt blood supply, leading to AVN months or years after the original injury.
• Sickle cell disease – abnormal red blood cells block small vessels supplying bone.
• Caisson disease – in deep-sea divers; nitrogen bubbles damage bone vasculature.
• Idiopathic – in 10-15% of cases, no clear cause is identified.
A note on COVID-related AVN: there was a marked rise in AVN diagnoses across India in 2021-2023, attributed to high-dose corticosteroid use during severe COVID-19 treatment. If you received intravenous or high-dose oral steroids during COVID and are now experiencing hip or groin pain, AVN should be specifically ruled out.
Early Symptoms (Don't Ignore These)
The earliest symptoms of AVN are usually subtle and easy to dismiss:
• Deep groin pain or hip pain, often initially attributed to “muscle strain”
• Pain that worsens with weight-bearing – walking, standing, climbing stairs
• Pain that improves with rest but returns immediately on activity
• Pain that wakes you at night, especially when changing position
• Slight limp that you may not notice but that family members might
• Reduced range of motion – difficulty crossing the legs, sitting cross-legged, or putting on socks
The pain is usually felt in the groin (front of the hip) rather than the side or back. Pain felt in the buttock or outer thigh is more often from back or muscle issues.
Have hip or groin pain that you’ve been dismissing?
AVN early is treatable without joint replacement. AVN late requires hip replacement. The difference between the two stages can be a matter of months. Send your symptoms or X-ray on WhatsApp (+91 7447799000) for a quick assessment.-
The Four Stages of AVN
-AVN progresses through well-defined stages, each with different treatment options:
Stage 1: Pre-collapse, no visible change on X-ray
The bone is starting to die but hasn’t collapsed yet. Plain X-rays look normal. Diagnosis requires MRI, which is highly sensitive at this stage. Treatment options are most varied here. Bone-preserving procedures can often prevent progression.
Stage 2: Pre-collapse, X-ray changes visible
The bone shows early changes on X-ray — sclerosis, mottling, cystic changes – but the spherical shape of the femoral head is still preserved. Core decompression and other joint-preserving surgeries are still effective.
Stage 3: Crescent sign early collapse
A “crescent sign” appears on X-ray, indicating the dead bone has started to collapse. The femoral head is still roughly spherical but is structurally compromised. This is a critical transition point joint-preserving surgery becomes less reliable, and the conversation often turns to whether to do a salvage procedure or wait for hip replacement.
Stage 4: Femoral head collapse and arthritis
The femoral head has flattened, the joint shape is destroyed, and secondary arthritis has developed in the hip socket. Hip replacement is the definitive treatment.
Non-Surgical Options (Limited Window)
For Stage 1 and early Stage 2 AVN, non-surgical management can sometimes slow or halt progression:
• Protected weight-bearing – using crutches or a walker to offload the affected hip for 4-8 weeks
• Bisphosphonate medications – may slow bone turnover and reduce collapse risk in some cases
• Hyperbaric oxygen therapy – emerging evidence suggests benefit in specific cases
• Statins and certain cholesterol medications – may have a role in steroid-induced AVN
• Lifestyle modification – stopping smoking, reducing alcohol, controlling underlying conditions
Honest caveat: non-surgical management works for a minority of patients and primarily in the earliest stages. Most patients with Stage 2 or beyond will need surgical intervention to preserve the joint.
Joint-Preserving Surgical Options
For Stage 1-2 AVN, several procedures can preserve the patient’s natural hip joint:
Core decompression with bone graft.
A small channel is drilled through the femoral neck to relieve pressure and stimulate new bone formation. Often combined with bone graft (from the patient’s own pelvis) or biologic adjuncts (stem cell concentrate, growth factors). Recovery is 6-12 weeks. Success rate depends on stage — 70-80% in early Stage 1, dropping to 30-40% in late Stage 2.
Vascularised fibular graft.
A piece of the patient’s fibula (smaller leg bone) is transplanted into the femoral head with its blood supply, providing structural support and new vascular ingrowth. More complex than core decompression, with longer recovery, but better outcomes in selected cases.
Tantalum rod implantation.
A porous metal rod is inserted to provide structural support. Less commonly performed now as long-term data has been mixed.
When Hip Replacement Becomes the Right Choice?
-For Stage 3 (collapse) and Stage 4 AVN, hip replacement is the most reliable treatment. Modern hip replacement surgery for AVN has excellent outcomes typically better than hip replacement for primary osteoarthritis, because AVN patients are often younger, more active, and have less degenerative change in the surrounding tissues.
The hip joint is replaced with a ball-and-socket implant. Recovery is straightforward, with most patients walking unassisted within 3-4 weeks and returning to most normal activities by 8-12 weeks.
A specific consideration in younger AVN patients: implant choice matters. Younger active patients typically need ceramic-on-ceramic or ceramic-on-polyethylene bearings rather than standard metal-on-polyethylene, because they will put more cumulative wear on the implant over their lifetime.
Why Delayed Diagnosis Is the Real Tragedy?
The recurring tragedy in AVN practice is patients who arrive with Stage 3 or Stage 4 disease who had Stage 1 symptoms 8-12 months earlier symptoms they didn’t recognise, or that their first doctor attributed to muscle strain or generic “hip pain”. By the time AVN is diagnosed correctly, the window for joint preservation has closed.
Two practical takeaways:
- Persistent groin or hip pain that doesn’t respond to 4-6 weeks of conservative treatment deserves an MRI, especially if any risk factors are present (steroid use, heavy alcohol, sickle cell, history of hip injury).
- The price of getting an MRI to rule out AVN is far lower than the price of replacing a hip 12 months later. Don’t let the cost of investigation deter you when symptoms persist.
Concerned About Possible AVN?
Dr. Utsav has fellowship training in joint preservation as well as hip replacement. Early-stage AVN deserves a surgeon who knows both options not one who defaults to replacement for every case.
Call: +91 7447799000
FAQ
Stage 1 AVN can sometimes be halted or partially reversed with prompt treatment.
Stage 2 and beyond involve some irreversible bone damage; joint-preserving surgery may stabilise the condition but cannot fully restore the original bon
Stage 1 AVN may be managed non-surgically in some cases. Stage 2 typically requires joint-preserving surgery. Stages 3-4 usually require hip replacement.
MRI is the gold standard it detects AVN before X-ray changes appear. X-rays detect Stage 2 and beyond. CT scans help in surgical planning.
If you received high-dose corticosteroids and now have any hip or groin pain, yes – an MRI is reasonable even if X-rays are normal. AVN can develop 6-24 months after steroid exposure.
Yes – bilateral AVN occurs in 30-70% of cases, especially when the cause is systemic (steroids, alcohol, sickle cell). If one hip is diagnosed, the other should be screened.
AVN most commonly affects patients aged 30-50, significantly younger than typical hip osteoarthritis. This younger profile is why joint-preserving surgery matters so much.