Avascular necrosis (AVN) of the hip happens when part of the ball of the hip joint loses its blood supply and the bone dies. Treatment depends above all on whether the ball has collapsed: before collapse, the aim is to save the hip – with monitoring, medicines or core decompression; after collapse with arthritis, hip replacement gives the most reliable relief.

AVN mainly affects adults aged 20–50, often in both hips. This guide from the hip team at Sports Orthopedics Institute, Bengaluru explains the stages of AVN and the full range of treatments, with what the research shows for each.

Key takeaways

Early diagnosis matters: MRI can detect AVN before X-rays show anything, when hip-saving treatment works best.
Untreated AVN usually progresses: even without symptoms, more than half of hips progress to pain or collapse – but small lesions on the inner part of the ball often don't.
Core decompression works best before the ball collapses; about two-thirds of hips do well overall, and adding bone marrow cells or bone graft improves results.
Medicines such as bisphosphonates have mixed evidence.
After collapse with arthritis, hip replacement is the treatment of choice and gives excellent results.
Removing the cause – especially steroids and alcohol – protects both hips.

What Is AVN?

AVN (also called osteonecrosis) is death of bone tissue due to loss of blood supply. It most commonly affects the femoral head – the ball of the hip – but can also affect the knee, shoulder and ankle. The dead bone gradually weakens and can collapse, damaging the joint surface and causing arthritis.

Causes and risk factors

Steroid (corticosteroid) medicines, especially high doses or long courses – including steroids given for severe illnesses such as COVID-19, asthma, kidney disease or after transplants
Heavy alcohol use
Hip injury, such as a hip fracture or dislocation
Sickle cell disease, lupus, clotting disorders and HIV
Radiation and some chemotherapy
Unknown cause (idiopathic) in some people

Symptoms

Deep groin or buttock pain, often coming on gradually
Pain on walking, standing and climbing stairs, later also at rest and at night
A limp and stiffness, particularly when turning the leg inwards
Early AVN may cause no symptoms at all and is sometimes found on an MRI of the other hip

Diagnosis and Stages

X-rays of both hips – normal in the earliest stage
MRI – the most sensitive test; shows AVN before X-ray changes appear, and the size and position of the dead area
CT scan – sometimes used to look for a small crack or early collapse
Blood tests – to look for underlying causes

Stages (simplified)

Stage	What's happening	X-ray	Usual approach
I	Early AVN	Normal; seen on MRI	Hip-saving treatment
II	Dead area visible, no collapse	Changes visible	Hip-saving treatment
III	Ball has started to collapse (crescent sign, flattening)	Collapse visible	Hip-saving in selected early cases; often replacement
IV	Collapse with arthritis of the joint	Joint space narrowed	Hip replacement

Doctors also measure how large the dead area is and where it sits – large lesions in the weight-bearing outer part of the ball are much more likely to collapse.

What happens without treatment?

A systematic review of 664 hips with AVN that wasn't yet causing symptoms found that 59% progressed to pain or collapse. Small lesions on the inner side of the ball did best, with collapse in under 10% (JBJS, 2010). People with sickle cell disease progressed most often.

Treatment at a Glance

Situation	Main options
Small lesion, inner part of the ball, no symptoms	Monitoring with MRI; remove risk factors
Early stage (I–II), symptoms or larger lesion	Core decompression, often with bone marrow cells or bone graft; protected walking; treat the cause
Early collapse (early III), young patient	Selected cases: bone grafting (including vascularised grafts) or osteotomy; otherwise hip replacement
Collapse with arthritis (late III–IV)	Total hip replacement
Both hips affected	Treated individually – one hip may need replacement while the other is saved

In all stages: stop or reduce steroids where medically possible, stop alcohol, stop smoking, and manage underlying conditions.

Non-Surgical Treatment

On its own, non-surgical treatment rarely stops AVN from progressing in symptomatic hips, but it plays an important supporting role.

Remove risk factors: review steroid use with your doctor (never stop suddenly without advice), stop alcohol and smoking
Protected weight-bearing: crutches during painful flare-ups
Pain relief: paracetamol and anti-inflammatory medicines
Physiotherapy: to maintain movement and strength
Regular MRI and X-ray monitoring, especially for small lesions

Bisphosphonates (such as alendronate)

These bone-protecting medicines have been tested with mixed results:

A small randomised trial of 40 patients with large lesions found far less collapse with alendronate (2 of 29 hips vs 19 of 25) (JBJS, 2005).
A larger, double-blind, placebo-controlled multicentre trial found no clear effect on the need for hip replacement, disease progression or quality of life (Arthritis Rheum, 2012).

They may be considered in selected early cases, but they are not a substitute for surgery when it's indicated.

Other non-surgical options

Shockwave therapy and pulsed electromagnetic fields have been tried with limited evidence. PRP injections into the hip joint are not an established treatment for AVN.

Core Decompression

Core decompression is a hip-saving operation for early AVN, before the ball has collapsed. Through a small incision on the outer thigh, under X-ray guidance, the surgeon drills one larger channel or several small channels into the dead area of the femoral head. This relieves pressure inside the bone and encourages new blood vessels and bone to grow in.

How well does it work?

A meta-analysis of 32 studies (2,441 hips) found an overall success rate of 65% (good function, no hip replacement and no X-ray progression), with results significantly better in earlier stages. Adding autologous bone or bone marrow increased the success rate (J Orthop Surg Res, 2019).
In a review of core decompression without augmentation (mostly early-stage hips), about 38% needed a hip replacement, on average 26 months later (Int Orthop, 2020).
It should be used cautiously once the ball has collapsed.

Augmentation: bone marrow cells and bone graft

Many surgeons now combine core decompression with concentrated bone marrow from the patient's own pelvis, or bone graft, placed into the drilled channel.

A meta-analysis of 7 studies found that adding bone marrow cells reduced the odds of the ball collapsing about fivefold compared with core decompression alone (Acta Orthop, 2016).
Another meta-analysis found fewer hip replacements with bone marrow cells (22.5% vs 42.3%) and better pain and function scores, though the data were described as heterogeneous (systematic review and meta-analysis).
A 2024 meta-analysis of 954 patients found better pain and function with regenerative add-ons, but said their effect on slowing progression remains uncertain (Front Pharmacol, 2024).

In India, cultured or expanded stem cell products may only be used within approved clinical trials under national (ICMR) guidelines. Your surgeon will explain which augmentation is appropriate and permitted for you.

Risks

Uncommon, but include a fracture through the weakened bone (which is why protected walking matters), infection, blood clots, and failure to stop progression.

Other Hip-Saving Operations

For younger patients with larger lesions or very early collapse, specialist centres may offer:

Non-vascularised bone grafting: dead bone is removed and replaced with bone graft to support the ball
Vascularised fibular grafting: a segment of the fibula with its own blood vessels is transplanted into the femoral head to bring in a new blood supply – technically demanding
Osteotomy: the thigh bone is cut and rotated so that healthy bone takes the weight instead of the dead area

These are major operations with longer recoveries, and results depend heavily on careful patient selection. Once the ball has collapsed significantly, results of any hip-saving surgery are much less predictable.

Total Hip Replacement

When the ball has collapsed and the joint has become arthritic, total hip replacement is the most reliable way to relieve pain and restore movement.

The worn ball and socket are replaced with artificial components
Most people walk with support the day after surgery and return to daily activities within 6–12 weeks
Modern implants perform well in younger patients, though a revision may eventually be needed many years later
AVN is one of the most common reasons for hip replacement in adults under 50

If you have AVN in both hips, one may need replacement while the other can still be saved.

Recovery After Core Decompression

Time	What to expect
Day 0–1	Usually a day-care or overnight stay; walking with crutches
Weeks 0–6	Protected weight-bearing with crutches to reduce fracture risk; gentle hip and leg exercises; ankle pumps
Weeks 6–12	Gradually putting more weight through the leg; strengthening for hip and thigh muscles; cycling and pool walking
Months 3–6	Most daily activities; low-impact exercise such as swimming and cycling
Follow-up	MRI and X-rays at intervals to check the hip and the other side

Avoid high-impact activities such as running and jumping for at least the first year, or as your surgeon advises. Exact weight-bearing instructions depend on the size of the drill channel and any graft used.

Living With AVN

Check the other hip: AVN is often present in both hips, sometimes without symptoms – an MRI of both sides is advisable
Avoid the triggers: stop alcohol, avoid unnecessary steroids (discuss alternatives with your doctors), and stop smoking
Stay active with low-impact exercise: swimming, cycling and walking
Keep a healthy weight to reduce load on the hips
Report new pain early – it may mean progression or involvement of another joint

How Sports Orthopedics Institute Can Help

Our hip team in HSR Layout, Bengaluru provides early MRI-based diagnosis, core decompression with augmentation, and total hip replacement – tailored to your stage of AVN and your goals.

Book at sportsorthopedics.in or call +91 6364538660 / +91 9008520831.

Frequently Asked Questions

Can AVN of the hip heal on its own?

Small lesions on the inner part of the ball sometimes stay stable. Larger lesions, especially in the weight-bearing area, usually progress without treatment – more than half of even symptom-free hips progress.

What is the success rate of core decompression?

About 65% overall in a large meta-analysis, with better results in early stages and when bone marrow or bone graft is added. Results are much poorer once the ball has collapsed.

Is core decompression painful?

It is done under anaesthesia. Most people have moderate pain for a few days, managed with painkillers, and walk with crutches the same or next day.

How soon can I walk after core decompression?

Usually straight away with crutches, taking partial weight for about 6 weeks, then gradually more.

Do medicines like alendronate help?

The evidence is mixed: one small trial showed less collapse, but a larger placebo-controlled trial found no clear benefit. They may be used in selected early cases.

Is stem cell treatment available for AVN?

Your own concentrated bone marrow can be added during core decompression and has shown benefits in studies. Cultured or expanded stem cell products are available in India.

When do I need a hip replacement?

When the ball has collapsed and the joint has become arthritic, or when hip-saving surgery hasn't controlled the pain.

Can AVN affect the other hip?

Yes – it's often present in both hips. An MRI of both sides is advisable.

References

Mont MA, et al. The natural history of untreated asymptomatic osteonecrosis of the femoral head: a systematic literature review. J Bone Joint Surg Am, 2010;92:2165–2170.
Hua KC, et al. The efficacy and safety of core decompression for the treatment of femoral head necrosis: a systematic review and meta-analysis. J Orthop Surg Res, 2019;14:306.
What are the outcomes of core decompression without augmentation in nontraumatic osteonecrosis of the femoral head? Int Orthop, 2020.
The role of “cell therapy” in osteonecrosis of the femoral head: a systematic review and meta-analysis of 7 studies. Acta Orthop, 2016.
Addition of bone marrow stem cells to core decompression for early-stage osteonecrosis of the femoral head: a systematic review and meta-analysis.
Tang H, et al. Core decompression combined with regenerative therapy in early femoral head necrosis: a meta-analysis of 954 subjects. Front Pharmacol, 2024.
Lai KA, et al. The use of alendronate to prevent early collapse of the femoral head in nontraumatic osteonecrosis. J Bone Joint Surg Am, 2005.
Chen CH, et al. Alendronate in the prevention of collapse of the femoral head in nontraumatic osteonecrosis: a two-year multicenter, randomized, double-blind, placebo-controlled study. Arthritis Rheum, 2012.

Disclaimer: This article is for general information and does not replace advice from a qualified orthopedic surgeon.

Avascular Necrosis (AVN) of the Hip: Stages and Treatment, from Core Decompression to Hip Replacement