What are the management options for avascular necrosis?

Management Options for Avascular Necrosis

The management of avascular necrosis (AVN) should be stage-based, with early-stage disease treated with conservative measures and core decompression, while advanced stages with articular collapse require joint replacement surgery. 1

Diagnosis and Staging

• MRI is the gold standard for diagnosis, especially in early stages when X-rays appear normal
• Both sides should be imaged when evaluating hip pain, even if symptoms are unilateral 1
• The Ficat and Arlet classification is most commonly used for staging:
  • Stage I-II: Early disease with preserved joint surface
  • Stage III-IV: Advanced disease with articular collapse 1, 2
• Necrotic volume assessment is critical:
  • ≥30% necrotic volume: 46-83% risk of collapse
  • <30% necrotic volume: <5% risk of collapse 1

Treatment Algorithm

1. Early-Stage AVN (Ficat and Arlet Stages I-II)

• Conservative management:

  • Address modifiable risk factors:
    • Reduce/eliminate corticosteroid use when possible
    • Manage hyperlipidemia (consider statins)
    • Eliminate alcohol consumption 1
  • Pain management:
    • First-line: Acetaminophen and NSAIDs (use with caution in elderly or those with renal dysfunction)
    • Advanced pain control: Opioids for severe pain (with reduced dosing in renal dysfunction) 1
  • Physical therapy and gentle mobilization once acute pain subsides 1
  • Pharmacologic interventions:
    • Bisphosphonates to improve bone density and prevent progression (with calcium and vitamin D supplementation) 1

• Surgical interventions:

  • Core decompression (first-line surgical intervention) which can be supplemented with:
    • Autologous bone marrow cells
    • Vascular fibular grafting
    • Electric stimulation 1, 3
  • Recent therapeutic advances using mesenchymal stem cells show promise for improving functional prognosis 1, 2

2. Advanced-Stage AVN (Ficat and Arlet Stages III-IV)

• Total joint replacement is the main treatment for advanced stages with articular collapse 1, 2
• Alternative surgical options:
  • Resurfacing hemiarthroplasty for femoral or humeral head AVN with articular collapse
  • For talar AVN: Talar resection/replacement with arthroplasty or tibiotalar joint fusion 1

Special Considerations for Different Anatomical Sites

Femoral Head AVN (Most Common - >75% of Cases)

• Follow the general algorithm above 2
• Total hip replacement accounts for 10% of indications for hip replacements in the US 1

Humeral Head AVN

• Similar treatment principles apply
• Options include core decompression, vascularized bone grafts, and shoulder arthroplasty 4

AVN in Special Populations

• HIV-infected patients:

  • Symptomatic AVN often ultimately requires joint replacement
  • Routine radiographic monitoring in asymptomatic persons is not recommended
  • Consider bisphosphonate therapy if bone densitometry demonstrates osteopenia 1

• Sickle cell disease patients:

  • AVN is a common cause of severe chronic pain
  • Treatment options follow the general algorithm but outcomes may be more limited 1

• Post-transplant patients:

  • Higher risk due to immunosuppressive therapy and prior dialysis
  • May require surgical intervention for pain management 1

Monitoring and Follow-up

• Early diagnosis allows for possible surgical prevention to prevent articular collapse 1
• Regular follow-up imaging to assess disease progression
• Adjust treatment based on clinical response and disease progression

Pitfalls and Caveats

• Conservative or nonoperative management alone has generally proven unsuccessful in halting disease progression 5
• Results with established surgical procedures can be inconsistent and sometimes disappointing 5
• Early intervention is critical as treatment becomes more challenging and less effective once articular collapse occurs 1, 2
• Even with clinical improvement, radiologic progression may continue in many cases 5