Osteonecrosis of the Hip (Avascular Necrosis): Symptoms, Diagnosis, Treatment & Recovery

What Is Osteonecrosis (Avascular Necrosis) of the Hip?

Osteonecrosis of the femoral head—also called avascular necrosis (AVN)—occurs when blood flow to the ball of the hip joint is disrupted. Without adequate blood supply, bone cells die, the structure weakens, and the spherical shape can collapse, leading to arthritis and significant pain. Early recognition is crucial because some hips can be preserved before collapse.

Common Symptoms

• Groin pain with standing, walking, or stairs; may radiate to the buttock or thigh.
• Stiffness and reduced range, especially internal rotation and flexion.
• Night pain or aching after activity; limp with increasing severity.
• Mechanical pain and catching once the femoral head begins to collapse.

Causes & Risk Factors

Osteonecrosis can be traumatic (after a displaced femoral neck fracture or hip dislocation) or non-traumatic. Non-traumatic causes and risk factors include:

• Systemic steroids (long courses or high doses), organ transplant immunosuppression.
• Excess alcohol intake.
• Haematologic and metabolic conditions: sickle cell disease, Gaucher disease, hyperlipidaemia.
• Autoimmune disorders: lupus and others.
• Barotrauma/decompression (diving), radiation therapy, chemotherapy.
• Idiopathic (no identifiable cause) in a significant number of patients.

How We Diagnose Osteonecrosis

We combine a careful history and examination with targeted imaging to confirm the diagnosis, determine the stage of disease, and guide treatment.

Clinical assessment

• Pain pattern, risk factor review (steroids, alcohol, systemic disease), and gait assessment.
• Hip range of motion and impingement testing; assessment for leg length discrepancy if collapse has occurred.

Imaging

• X-rays: may be normal early; later show sclerosis, subchondral lucency (“crescent sign”), and deformity.
• MRI: the most sensitive test for early disease; maps the size and location of the necrotic area.
• CT (selected cases): useful for assessing subchondral collapse and surgical planning.

We reference validated staging systems (e.g., early pre-collapse vs post-collapse) to align management with prognosis.

Non-Operative Treatment

In early, pre-collapse disease, non-operative care aims to reduce pain, limit further structural stress, and optimise bone health while we monitor the lesion.

1) Education & load modification

• Temporary activity modification to reduce impact and torsional loads (avoid running, jumping, deep squats).
• Short period of off-loading or partial weight-bearing if pain is high (as advised).
• Switch to low-impact conditioning (bike, pool) to maintain fitness.

2) Physiotherapy

• Hip and lumbopelvic control (gluteals and deep rotators) to reduce joint shear.
• Mobility within comfort; strategies for gait and transitional movements.

3) Optimising bone and metabolic health

• Review of modifiable risks (steroid exposure where possible, alcohol intake, lipids).
• Nutritional and general health optimisation (vitamin D/calcium if deficient; smoking cessation).

4) Medications & injections

• Pain relief strategies tailored to you.
• Intra-articular corticosteroid is generally avoided in AVN due to concerns about cartilage health.
• Bone-active agents have mixed evidence; we discuss potential benefits and uncertainties case-by-case.

Monitoring: We typically repeat imaging at intervals to assess for progression, especially if symptoms change.

Hip Preservation Surgery (Pre-Collapse & Early Collapse)

When disease is detected before significant collapse, surgical options may reduce pain and delay or prevent arthritis. Suitability depends on lesion size, location, symptoms, and your overall health.

• Core decompression: a narrow channel relieves intra-osseous pressure and may stimulate re-vascularisation in early disease.
• Biologic augmentation (selected cases): procedures may be combined with bone marrow concentrate or bone grafting; current evidence continues to evolve.
• Structural grafting/osteotomy (selected centres): used for larger, focal lesions to support weakened bone or shift load away from the affected area.

We will discuss expected benefits, risks, rehabilitation, and the likelihood of later hip replacement if disease progresses.

Hip Replacement for Advanced Osteonecrosis

Once the femoral head collapses and the joint surface becomes irregular, pain and stiffness escalate. In these cases, hip replacement provides reliable pain relief and function.

• Modern implants and muscle-sparing techniques support faster early recovery.
• We tailor implant selection to bone quality and anatomy; both sides of the joint (ball and socket) are resurfaced.
• Typical pathway includes pre-operative optimisation, enhanced recovery protocols, and structured rehabilitation.

For younger patients, we discuss implant longevity, activity guidance, and long-term follow-up.

Risks & Considerations

• Progression risk: larger or weight-bearing–zone lesions are more likely to collapse.
• Procedure risks: infection, bleeding, clots (rare), nerve irritation, fracture, stiffness.
• Residual symptoms: pain may persist if arthritis is advanced or if co-pathologies are present.

Recovery & Rehabilitation

Recovery depends on the stage at diagnosis and the treatment chosen:

1. Non-operative: gradual symptom improvement over weeks to months with load management and targeted therapy.
2. Core decompression: short period of protected weight-bearing; progressive return to low-impact activity as pain settles.
3. Hip replacement: early walking with aids, functional independence typically improves over 6–12 weeks, with strength and endurance gains continuing for months.

Prevention & Lifestyle Tips

• Discuss the lowest effective dose and duration if long-term steroids are required.
• Moderate or cease alcohol intake; address lipid disorders with your GP.
• Maintain bone health: nutrition, vitamin D (if deficient), and resistance training within comfort.
• Seek early assessment for new groin pain, especially if risk factors are present.

When Should I See a Hip Specialist?

If you have persistent groin pain, a known risk factor (steroids, alcohol, systemic disease), or a prior hip injury, early review is wise. Identifying osteonecrosis before collapse expands your options for hip preservation.

Osteonecrosis of the Hip — FAQs