What are the management options for avascular necrosis of the hip?

Management of Avascular Necrosis of the Hip

Total hip arthroplasty is the definitive treatment for advanced avascular necrosis of the hip with femoral head collapse, while joint-preserving procedures like core decompression are recommended for early-stage disease without collapse. 1

Diagnosis and Staging

• MRI is the gold standard for diagnosis of avascular necrosis (AVN), especially in patients with normal radiographs but persistent hip pain 1
• Both hips should be imaged as AVN can be bilateral 1
• The Ficat and Arlet classification system is commonly used for staging:
  • Stage I: Normal radiographs but MRI changes
  • Stage II: Radiographic changes without femoral head collapse
  • Stage III: Femoral head collapse
  • Stage IV: Secondary osteoarthritis with joint space narrowing 2

Risk Factors

• Corticosteroid treatment is a major risk factor 1, 2
• Alcohol abuse significantly increases risk 1, 2
• Hemoglobinopathies, particularly sickle cell disease 1
• Hyperlipidemia 1
• Hypercoagulable states 1
• Late presentation is associated with worse outcomes 1

Non-Surgical Management (Early Stages)

• Weight reduction and protected weight-bearing with walking aids (canes or walkers) to reduce mechanical stress on the femoral head 1
• Bisphosphonates may help prevent bone collapse in early stages 1
• Non-surgical management alone has very limited efficacy and is generally reserved only for the earliest stages 3
• NSAIDs and analgesics for symptomatic pain relief, though they do not alter disease progression 4

Surgical Management

Early Stage Disease (Pre-collapse: Ficat Stages I-II)

• Core decompression (CD) is the most common joint-preserving procedure for early-stage AVN 3
  • Traditional single-tunnel technique uses a cannulated drill bit inserted into the lateral cortex of the proximal femur 5
  • Multiple small-diameter drilling technique reduces fracture risk 5, 6
• Augmentation options for core decompression:
  • Bone marrow aspirate concentrate to enhance bone repair 3, 5
  • Demineralized bone matrix 3
  • Bone morphogenetic proteins 3
  • Tantalum rods for structural support 5
  • Mesenchymal stem cells and platelet-rich plasma 5

Advanced Disease (Post-collapse: Ficat Stages III-IV)

• Total hip arthroplasty is the treatment of choice for advanced AVN with femoral head collapse 2
• For younger patients with dysplasia or varus/valgus deformity, osteotomy and other joint-preserving procedures should be considered 4
• Cemented arthroplasty improves hip function and is associated with lower residual pain compared to uncemented arthroplasty, especially in elderly patients 4

Treatment Algorithm Based on Stage

1. Stage I (Pre-symptomatic with MRI changes only):

   • Protected weight-bearing
   • Bisphosphonates
   • Consider core decompression if risk factors cannot be modified 1, 3

2. Stage II (Pre-collapse with radiographic changes):

   • Core decompression with biological augmentation (bone marrow aspirate, stem cells) 3, 5
   • Osteotomy for young patients with specific anatomical abnormalities 4

3. Stage III-IV (Post-collapse with or without secondary osteoarthritis):

   • Total hip arthroplasty 2
   • Cemented arthroplasty for elderly patients to reduce periprosthetic fracture risk 4

Prognosis

• Untreated AVN inevitably progresses to early degenerative joint disease 1
• AVN causes up to one-third of all total hip arthroplasties in patients under 60 years 1
• Ten-year survivorship of the hip joint after appropriate joint-preserving treatment can reach 75% in suitable candidates 7
• Early intervention is critical - late presentation significantly worsens outcomes 1

Monitoring and Follow-up

• Regular radiographic follow-up every 3-6 months in early stages to monitor for progression 2
• MRI follow-up to assess response to joint-preserving treatments 1
• Patients should be educated about the importance of avoiding risk factors such as alcohol and corticosteroids 2