What is the treatment for avascular necrosis?

Treatment of Avascular Necrosis

The treatment of avascular necrosis depends critically on disease stage: for early pre-collapse disease (stages I-II), core decompression with bone grafting combined with protected weight-bearing and bisphosphonates offers the best chance to preserve the joint, while late-stage disease with articular collapse (stages III-IV) requires total joint arthroplasty. 1

Diagnostic Staging First

Before initiating treatment, obtain MRI imaging to stage the disease, as this is the preferred diagnostic method and determines the entire treatment algorithm 1, 2. Standard radiographs miss early disease and should only be used initially to exclude fracture, tumor, or primary arthritis 2. The Ficat and Arlet classification system guides treatment decisions based on whether articular collapse has occurred 3.

Early-Stage Disease (Pre-Collapse, Stages I-II)

Conservative Management

• Implement strict protected weight-bearing immediately for patients with MRI-confirmed AVN but no symptoms or only early symptoms 1, 2
• Prescribe bisphosphonates to prevent bone collapse in early stages, as recommended by the American College of Rheumatology 1
• Recommend weight reduction and walking aids (canes or walkers) to reduce mechanical stress on the affected joint 1, 2

Surgical Intervention for Early Disease

Core decompression with bone substitute filling is the primary surgical option for younger patients with early-stage disease 1, 4. This procedure:

• Shows 92.3% success rate for stage I disease when patients comply with strict non-weight-bearing protocols 5
• Demonstrates 54-100% improvement rates for stage IIA disease with proper patient selection 5
• Should be performed before articular surface collapse occurs, as outcomes deteriorate significantly once collapse begins 3, 5

Critical technical point: Multiple small drilling techniques reduce fracture risk compared to traditional single-tunnel approaches 6. Adjunctive bone grafting from the posterior iliac crest should be performed in most cases 5.

Post-Operative Protocol

• Enforce strict non-weight-bearing for the prescribed period, as non-compliance reduces success rates from >90% to 50% even in early-stage disease 5
• Perform regular radiographic follow-up to monitor for disease progression or femoral head collapse 1

Late-Stage Disease (Post-Collapse, Stages III-IV)

Total hip arthroplasty is necessary for late-stage AVN with articular collapse, as no conservative or joint-preserving procedures are effective once the articular surface has collapsed 1, 2. Key considerations:

• Use cemented femoral fixation in elderly patients with poor bone quality to reduce periprosthetic fracture risk 2
• Consider joint-preserving osteotomy procedures only in young adults with specific anatomical abnormalities like dysplasia or varus/valgus deformity 2
• AVN causes up to one-third of all total hip arthroplasties in patients under 60 years of age 2

Symptomatic Management Across All Stages

• NSAIDs and analgesics provide symptomatic pain relief but do not alter disease progression 2
• Pain is typically severe and worsened by weight-bearing 1

Special Population Considerations

Pediatric Oncology Patients

There is no evidence-based consensus on managing osteonecrosis in pediatric ALL patients 7. However:

• Core decompression with bone substitute filling has been used successfully in pediatric oncology patients 4
• Systematic early screening with serial MRI might reduce morbidity, though this is not realistic in routine practice 7
• Teriparatide carries a black box warning against use in children due to osteosarcoma risk 7

High-Risk Patients (Corticosteroid Use, HIV)

For patients requiring corticosteroids, especially HIV-positive individuals, use extreme caution 8:

• Limit to absolute minimum dose and shortest duration (ideally <5 mg prednisone equivalent for <3 months) 8
• Initiate prophylactic bisphosphonate therapy immediately if steroids required ≥3 months 8
• Provide calcium 1,200 mg daily and vitamin D 800 IU daily 8
• Obtain baseline DXA scan before corticosteroid initiation 8
• Approximately 5% of HIV patients have asymptomatic AVN on MRI, indicating subclinical disease may already be present 8

Critical Pitfalls to Avoid

• Never rely on normal radiographs to exclude AVN—MRI is required for diagnosis, as standard films miss early disease 2, 8
• Do not delay treatment once diagnosed, as untreated AVN inevitably leads to early degenerative joint disease 2
• Avoid core decompression once articular collapse has occurred (stage III or beyond), as success rates drop dramatically and arthroplasty becomes necessary 3, 5
• Do not underestimate the importance of strict weight-bearing compliance post-operatively, as this single factor can determine success or failure 5

Prognosis

Late presentation is the major negative prognostic factor 2. For early intervention with core decompression: stage I disease shows >90% success, stage IIA shows 54-100% success, but stage IIB drops to 50% success even with optimal treatment 5. Joint-preserving procedures in appropriately selected patients show 75% ten-year hip survivorship with mean Harris hip scores of 82 9.