At what stage of AVN is core decompression most effective?

Core decompression achieves its best results in ARCO Stage I and Stage II AVN — when the femoral head remains spherical and the subchondral bone is intact. Once subchondral fracture (crescent sign, Stage III) or femoral head collapse (Stage IV) has occurred, core decompression is unlikely to prevent progression and hip replacement becomes the more appropriate treatment.

How successful is core decompression at preventing hip replacement?

Success rates for core decompression depend heavily on AVN stage and the size of the necrotic segment. In Stage I disease with a small necrotic area, 70 to 80% of patients avoid femoral head collapse at 5 years. In Stage II disease with a large necrotic segment, success rates are lower at 50 to 60%. Adding biological augmentation such as bone marrow concentrate improves outcomes in some studies.

Is there a risk of fracture during or after core decompression?

Femoral neck fracture is a rare but serious potential complication of core decompression, occurring in approximately 1 to 3% of cases when the channel is too large or positioned suboptimally. Using small-diameter drill systems and avoiding weight-bearing for 6 to 8 weeks significantly reduces this risk. Your surgeon will advise on the specific precautions for your procedure.

When can I return to full weight-bearing after core decompression?

Protected partial weight-bearing with crutches is maintained for 6 to 8 weeks after core decompression to allow the drill channel to fill and the revascularisation process to begin without mechanical loading the femoral head. Your surgeon will gradually advance weight-bearing based on serial X-ray and MRI evidence of healing at each follow-up.

Does core decompression always work?

Core decompression does not work for every patient, and some cases progress to femoral head collapse despite the procedure. If this occurs, total hip replacement remains an excellent and reliable option that provides complete pain relief and full restoration of hip function. Core decompression is attempted first in suitable candidates because it preserves the native hip if successful.

Core Decompression for Avn

Core Decompression for Avascular Necrosis (AVN) is an orthopaedic procedure that relieves raised pressure within the femoral head by removing a core of bone — promoting revascularisation, halting disease progression, and delaying or preventing the need for hip replacement in patients with early-stage AVN.

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Overview

Core Decompression for Avascular Necrosis is performed in the early stages of AVN — when the femoral head is still round and has not collapsed — to reduce the elevated intraosseous pressure that impairs blood flow to the bone, stimulate new vascular ingrowth, and promote revascularisation of the ischaemic bone before irreversible collapse occurs. A channel is drilled through the femoral neck into the area of necrotic bone, which decompresses the bone, triggers a healing response, and — in suitable cases — is supplemented with bone graft, stem cells, or biological augmentation to enhance the regenerative potential. When performed at the correct stage, core decompression can preserve the native hip and significantly delay or avoid total hip replacement.

Types of Core Decompression and Augmentation

Core decompression can be performed as a standalone procedure or combined with biological augmentation depending on the stage and extent of AVN.

Standard Core Decompression (single or multiple drilling channels into the femoral head)
Core Decompression with Autologous Bone Graft (structural support and biological stimulation)
Core Decompression with Vascularised Fibula Graft (for larger necrotic areas)
Core Decompression with Bone Marrow Aspirate Concentrate (stem cell augmentation)
Core Decompression with Synthetic Bone Substitute (for filling the decompression channel)

Risk Factors for Avascular Necrosis

Avascular necrosis of the femoral head develops when the blood supply to the bone is interrupted by a variety of conditions. Identifying and modifying these risk factors is essential alongside surgical treatment.

Long-term corticosteroid use — the most common cause of non-traumatic AVN worldwide
Excessive alcohol consumption causing fat emboli disrupting the femoral head circulation
Hip trauma including femoral neck fracture or hip dislocation disrupting the vascular supply
Sickle cell disease causing vaso-occlusion and bone infarction
Systemic lupus erythematosus and other autoimmune conditions often treated with steroids
Dysbaric osteonecrosis from deep sea diving or compressed air work

Avascular Necrosis Symptoms

AVN of the femoral head progresses through defined radiological stages, and symptoms typically appear in the intermediate stages when subchondral collapse begins. Early stage disease may be asymptomatic.

Groin pain — the most characteristic symptom — often worse on weight-bearing and activity
Hip stiffness and reduced range of internal rotation compared to the other hip
Night pain in the hip waking the patient from sleep as the disease progresses
Antalgic limp and difficulty walking distances
Sudden worsening of pain from subchondral fracture just before collapse
Bilateral hip symptoms — AVN is bilateral in up to 80% of cases from systemic causes
Referred knee pain from hip pathology in some patients
Difficulty with daily activities — putting on shoes, socks, rising from chairs — from restricted hip movement

Key Benefits

Discover the advantages of choosing our core decompression for avn services.

Decompresses raised intraosseous pressure — the primary mechanism of femoral head ischaemia

Short minimally invasive procedure with small incision and minimal tissue disruption

Prevents or significantly delays femoral head collapse in appropriately staged early AVN

Preserves the native hip joint avoiding or delaying the need for total hip replacement

Crutch-assisted mobilisation from day one allows reasonable daily function during recovery

Clinical Features

The technology, techniques and clinical approach behind our core decompression for avn.

MRI bilateral hip assessment confirms exact ARCO staging before surgical planning

Fluoroscopic real-time guidance in both AP and lateral planes during guide wire placement

Bone marrow aspirate concentrate augmentation available to enhance revascularisation

Protected weight-bearing protocol for 6 to 8 weeks prevents premature femoral head collapse

Serial MRI and X-ray follow-up monitors revascularisation response at 3, 6, and 12 months

Preparation Instructions

- Complete MRI of the hip (both hips) to accurately stage the AVN and assess the size of the necrotic segment
- Provide blood results including CBC, coagulation, blood group, kidney function, and metabolic bone markers
- Stop corticosteroids in collaboration with the prescribing physician wherever clinically possible
- Stop smoking and alcohol consumption to protect the healing response
- Stop anticoagulants 5 to 7 days before surgery under supervision
- Fast for 6 to 8 hours before surgery
- Arrange crutches or walker and home support for 4 to 6 weeks of restricted weight-bearing post-discharge
- Discuss the expected outcomes, limitations, and realistic timeline for improvement with your orthopaedic surgeon

The Procedure

Step-by-step guide to what you can expect during your core decompression for avn procedure.

MRI Staging and Candidacy Assessment
Your orthopaedic surgeon reviews bilateral hip MRI to accurately stage the avascular necrosis using the ARCO or Ficat classification, measure the necrotic segment volume, and assess the integrity of the subchondral bone — confirming that the femoral head is still round and has not yet collapsed, making core decompression a viable and potentially effective intervention.
Pre-Operative Risk Factor Modification
Your surgeon works with you to modify the risk factors contributing to your AVN — discussing corticosteroid dose reduction with your prescribing physician, alcohol cessation, and smoking cessation. Addressing these factors before surgery significantly improves the biological environment for revascularisation after decompression.
General or Spinal Anaesthesia
General or spinal anaesthesia is administered and you are positioned on the fracture table to allow continuous fluoroscopic hip imaging throughout the procedure. The lateral hip skin is prepared in a sterile manner and a small incision is planned over the greater trochanteric region for guide wire entry.
Fluoroscopic Guide Wire Placement
Under continuous fluoroscopic imaging, a guide wire is directed precisely into the centre of the necrotic segment of the femoral head. Correct positioning is confirmed in both the AP and lateral planes on the X-ray screen before any drilling begins — accurate guide wire placement is the most critical technical step of the entire procedure.
Core Channel Drilling and Biological Augmentation
A cannulated drill is advanced over the guide wire to create one or more channels through the femoral neck and into the necrotic zone, directly decompressing the raised intraosseous pressure. The channel is then filled with autologous bone marrow aspirate concentrate, bone graft, or synthetic substitute to provide biological stimulation for revascularisation.
Protected Weight-Bearing and Follow-Up Plan
Crutch-assisted partial weight-bearing is commenced from the day after surgery and maintained for 6 to 8 weeks while revascularisation and bone healing begin. Your surgeon explains the serial MRI and X-ray schedule — at 3, 6, and 12 months — that will monitor the response to treatment and guide your progressive return to full weight-bearing.

What to Expect

Core Decompression is performed under general or spinal anaesthesia and takes 60 to 90 minutes. A guide wire is placed into the area of necrotic bone under fluoroscopic imaging guidance, and one or more core channels are drilled through the femoral neck using a cannulated reamer. Bone graft or biological augmentation is packed into the channel if planned. You will be on partial weight-bearing with crutches for 6 to 8 weeks post-operatively. Hospital stay is typically 1 to 2 days.

Recovery

After Core Decompression, strictly follow the prescribed weight-bearing restriction for 6 to 8 weeks to protect the femoral head while revascularisation and healing begin — premature full loading risks femoral head collapse. Continue all prescribed medications and comply with risk factor modification — stopping steroids where possible and completely stopping alcohol and smoking. Attend serial MRI and X-ray follow-ups at 3 months, 6 months, and 1 year to monitor the response to treatment. Contact your orthopaedic team immediately for sudden increase in hip pain or any new inability to bear weight.

Core Decompression for Avn

Overview

Types of Core Decompression and Augmentation

Risk Factors for Avascular Necrosis

Avascular Necrosis Symptoms

Key Benefits

Clinical Features

Preparation Instructions

The Procedure

MRI Staging and Candidacy Assessment

Pre-Operative Risk Factor Modification

General or Spinal Anaesthesia

Fluoroscopic Guide Wire Placement

Core Channel Drilling and Biological Augmentation

Protected Weight-Bearing and Follow-Up Plan

What to Expect

Recovery

Frequently Asked Questions

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