What is the treatment for avascular necrosis?

Treatment of Avascular Necrosis

The treatment of avascular necrosis should be based on disease stage, with conservative management for early stages (I-II) and surgical intervention for advanced stages (III-IV) with articular collapse. 1, 2

Understanding Avascular Necrosis

Avascular necrosis (AVN) is an ischemic or cytotoxic necrosis of epiphyseal bone resulting from disruption of blood supply, leading to cellular death and potential joint collapse. It most commonly affects the femoral head (>75% of cases), but can also involve the humeral head, knee, scaphoid, lunate, and talus 1, 2, 3.

Common risk factors include:

• Corticosteroid therapy
• Alcohol abuse
• Trauma
• Sickle cell disease
• Systemic lupus erythematosus
• Hypercholesterolemia 2, 3, 4

Diagnostic Approach

MRI is the preferred diagnostic method for AVN, especially in early stages when X-rays may appear normal 1. Approximately 5% of patients may be asymptomatic in early stages, but pain is often the trigger for diagnostic imaging 1.

Treatment Algorithm Based on Disease Stage

Stage I and II (Pre-collapse)

1. Conservative Management:

   • First-line analgesics: Regular paracetamol (acetaminophen) and NSAIDs (use with caution in elderly or those with renal dysfunction) 1
   • Advanced pain control: Opioids for severe pain (reduced dosing in renal dysfunction, avoid codeine due to side effects) 1
   • Bisphosphonates to improve bone density and prevent progression (with calcium and vitamin D supplementation) 1
   • Physical therapy and gentle mobilization once acute pain subsides 1
   • Risk factor management and activity modification 3

2. Joint-preserving Procedures:

   • Core decompression
   • Vascularized bone grafts 1, 3

Stage III and IV (Post-collapse)

1. Surgical Interventions:
   • Total joint replacement (arthroplasty) is the main treatment 1, 2
   • Arthroscopic debridement may be considered in select cases 3

Special Considerations

• Bisphosphonate-related AVN: Patients on bisphosphonate therapy may develop osteonecrotic lesions in the jawbone, particularly after dental extractions. These cases require treatment according to osteomyelitis protocol, which may include curettage or sequestrectomy 5

• Sickle Cell Disease: AVN is one of the most common causes of severe chronic pain in people with sickle cell disease, with limited treatment options currently available 6

• HIV and Post-transplant Patients: These populations may experience AVN causing severe pain, often requiring surgical intervention 1

Emerging Therapies

Recent therapeutic advances based on mesenchymal stem cells show promise for improving the functional prognosis of AVN, particularly in early stages 2. However, these approaches are still developing and not yet part of standard treatment protocols.

Pitfalls and Caveats

• Delay in diagnosis can lead to disease progression and poorer outcomes
• Fingertip necroses are an alarming symptom that may initially progress slowly over weeks but can rapidly deteriorate, indicating the need for early intervention 7
• If AVN threatens limb viability, immediate surgical intervention is necessary 7
• There is currently no consensus on the optimal treatment approach for all patients with AVN 4