What is the treatment for avascular necrosis?

Treatment of Avascular Necrosis

The treatment of avascular necrosis should be stage-based, with core decompression as the primary surgical option for early-stage disease and total joint replacement for advanced stages with articular collapse. 1

Understanding Avascular Necrosis

Avascular necrosis (AVN) is an ischemic or cytotoxic necrosis of epiphyseal bone that occurs through three main mechanisms:

• Vascular interruption
• Vascular occlusion
• Extravascular intraosseous compression 1, 2

The femoral head is affected in more than 75% of cases, though AVN can also occur in other joints including the knee, ankle, and shoulder 1, 3.

Risk Factors

Identifying and addressing risk factors is crucial for management:

• Corticosteroid therapy (leading cause of non-traumatic AVN)
• Alcohol consumption
• Blood disorders (sickle cell disease, lymphoma/leukemia)
• Metabolic conditions (hyperlipidemia, Gaucher disease)
• Immunological factors (HIV infection, post-transplantation)
• Other causes (radiation therapy, chemotherapy) 1

Diagnosis and Staging

MRI is the gold standard for diagnosis and staging of AVN 1. The Ficat and Arlet classification is most commonly used for femoral head AVN:

• Stage I and II: Early stages with preserved joint surface
• Stage III and IV: Advanced stages with articular collapse 1, 3

Assessment of necrotic volume is critical for prognosis:

• ≥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 Stage I and II)

Conservative management:

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

Surgical options for early-stage AVN:

• Core decompression: Primary surgical option for early-stage disease 1, 4
• Supplemental treatments:
  • Autologous bone marrow cell injection
  • Vascular fibular grafting
  • Electric stimulation 1

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

Surgical management:

• Total joint replacement: Main treatment for advanced stages with articular collapse 1, 3
• Alternative surgical options:
  • Resurfacing hemiarthroplasty for femoral or humeral head AVN
  • Talar resection/replacement with arthroplasty or tibiotalar joint fusion for talar AVN 1

Special Considerations

Pediatric Patients

• Core decompression with bone substitute filling has been used in pediatric oncology patients 4

Sickle Cell Disease

• AVN is a common cause of severe chronic pain in sickle cell disease
• Limited treatment options currently available 5

HIV-Infected Patients

• Will ultimately require hip replacement if symptomatic
• Routine radiographic monitoring not recommended in asymptomatic persons
• Consider bisphosphonate therapy if bone densitometry shows osteopenia 1

Emerging Therapies

Recent therapeutic advances based on mesenchymal stem cells show promise for improving the functional prognosis of AVN, particularly in early stages 1, 3.

Important Caveats

• Early intervention before subchondral collapse significantly improves outcomes 1
• AVN is often bilateral (70%-80%) in non-traumatic cases, requiring careful monitoring of both sides 1
• Adequate pain management is essential to prevent increased morbidity and delayed rehabilitation 1
• The treatment of AVN remains challenging, with ongoing debate about optimal management strategies, particularly for less common locations such as the carpus 2