What are the different techniques of core decompression for Avascular Necrosis (AVN) of the hip?

Core Decompression Techniques for Avascular Necrosis of the Hip

Core decompression for avascular necrosis (AVN) of the hip can be performed using several different techniques, with the traditional single-tunnel approach and multiple small drilling being the most common methods, each with specific advantages and disadvantages depending on the stage of disease and patient factors.

Traditional Core Decompression Techniques

• Single-tunnel core decompression: The classic technique involves using an 8-mm trephine inserted from below the greater trochanter into the center of the necrotic lesion, approaching within 5mm of the articular surface 1
• Multiple small drilling technique: A less invasive approach using multiple smaller drill holes to decrease the risk of fracture while still achieving decompression 2
• Core decompression with bone grafting: Involves removing the necrotic bone and replacing it with cancellous bone graft harvested from the intertrochanteric region to provide structural support 1

Advanced and Augmented Core Decompression Techniques

• Core decompression with tantalum rod insertion: Provides structural support to the femoral head after decompression to prevent collapse 2
• Core decompression with orthobiologics: Various biological augmentations can be added to enhance healing, including:
  • Bone marrow aspirate concentrate (BMAC)
  • Mesenchymal stem cells
  • Platelet-rich plasma (PRP)
  • Human umbilical cord mesenchymal stem cell extracts 2
• Core decompression with vascular fibular grafting: Combines decompression with a vascularized bone graft to provide both structural support and biological enhancement 3
• Core decompression with electrical stimulation: Uses electrical current to potentially stimulate bone healing after decompression 3

Combination Techniques

• Core decompression with valgus intertrochanteric osteotomy: Combines decompression with realignment of the femoral head to move the necrotic portion away from the weight-bearing surface 4
• Core decompression with autologous bone marrow cells: Enhances the traditional technique by introducing bone marrow cells to promote healing and revascularization 5

Effectiveness Based on Disease Stage

• For early stages (Ficat and Arlet stages I and II or pre-collapse):

  • Core decompression shows success rates of 84% for stage I and 63% for stage II, compared to 61% and 59% with conservative treatment 6
  • Patients with small necrotic lesions have significantly better outcomes, with only 7% requiring total hip replacement after core decompression and bone grafting 1

• For advanced stages (stage III or early collapse):

  • Core decompression shows lower success rates of approximately 29% 6
  • More advanced techniques like vascularized bone grafting may be considered 5

Surgical Considerations

• Proper patient selection is critical for success, with best results seen in early-stage disease before femoral head collapse 1, 6
• The size of the necrotic lesion is a significant prognostic factor, with lesions involving <30% of the femoral head having <5% progression to collapse 3
• CT imaging is valuable for preoperative planning, showing the location and extent of articular collapse that may not be visible on radiographs 3
• 3D-printed guide plates can improve surgical precision, decrease operative time, and reduce blood loss during core decompression 3

Complications

• Potential complications include subcapital fracture (especially with larger diameter drilling), pulmonary embolism, pneumonia, and thrombophlebitis 1
• The risk of fracture is lower with multiple small drilling techniques compared to traditional single large core decompression 2

Postoperative Management

• Protected weight-bearing is recommended for patients following core decompression procedures 7
• Regular follow-up with radiographic evaluation is essential to monitor disease progression 3

Core decompression remains a valuable joint-preserving procedure for early-stage AVN of the femoral head, with various technical modifications and biological augmentations available to potentially improve outcomes based on individual patient factors and disease characteristics 2, 5.