What is the management plan for a femur tunnel blowout?

Management of Femur Tunnel Blowout

The management of femur tunnel blowout requires prompt surgical intervention with extended cortical fixation techniques to salvage the tunnel integrity and ensure proper graft stability.

Identification and Assessment

• Femur tunnel blowout is a complication that can occur during ACL reconstruction, particularly at the outer cortical opening during revision procedures 1
• The blowout compromises the mechanical strength of the cortical bone at the tunnel opening, weakening the stability provided to fixation devices such as endobuttons 1
• Tunnel blowouts can occur at different locations:
  • Distal aperture facing into the joint (more common) 1
  • Intratunnel blowout at the outer cortical opening (rare) 1
  • Back wall blowout during anteromedial portal drilling 2

Surgical Management Options

Suspensory Fixation Modification

• Use of a suture disc placed directly over the proximal opening of the femoral tunnel on the lateral cortex 1
  • This technique involves tying the endobutton with a suture disc to provide additional stability
  • Cost-effective and readily available solution
  • Can be performed using the same prepared graft with minimal additional operative time

Alternative Fixation Techniques

• If the blowout occurs during primary ACL reconstruction, consider:
  • Adjusting the tunnel position to engage intact cortical bone 3
  • Using larger diameter fixation devices that span the defect 1
  • Employing supplementary fixation methods such as staples or screws 1

Revision Considerations

• For blowouts during revision procedures, options include:
  • Creating a new tunnel in a different location if adequate bone stock remains 4
  • Using bone grafting to fill the defect before attempting fixation 4
  • Employing the over-the-top technique plus lateral extra-articular tenodesis when femoral tunnel integrity is severely compromised 3

Intraoperative Precautions to Prevent Blowout

• When creating femoral tunnels, particularly through the anteromedial portal:
  • Use appropriate guide placement at the posterior aspect of the femoral footprint 5
  • Ensure adequate tunnel length (mean optimal length approximately 39.5 mm) 5
  • Maintain proper coronal angle of the femoral tunnel (approximately 30°) 5
  • Avoid excessive reaming that could weaken the cortical bone 5

Postoperative Management

• Following successful management of femur tunnel blowout:
  • Implement standard postoperative protocols including analgesia, thromboprophylaxis, and rehabilitation 6
  • Regular paracetamol administration should continue throughout the recovery period 6
  • Opioids should be used with caution, especially in patients with renal dysfunction 6
  • Early mobilization should be encouraged to reduce the risk of DVT 6

Monitoring and Follow-up

• Close monitoring for:
  • Signs of graft failure or instability 3
  • Infection risk (follow hospital antibiotic protocols) 6
  • Pain management needs during rehabilitation 6
  • Progress of functional recovery 1

Special Considerations for Elderly Patients

• In elderly patients with femur tunnel blowout:
  • Consider bone quality when selecting fixation methods 6
  • Be aware of increased risks of complications in patients with sarcopenia 6
  • Optimize peri-operative fluid management to reduce morbidity and hospital stay 6
  • Implement active warming strategies during and after surgery to prevent hypothermia 6

Pitfalls and Caveats

• Misplaced femoral tunnels are the most common cause of ACL reconstruction failure 3
• Tunnel malposition leads to higher incidence of postoperative meniscal lesions, inferior clinical outcomes, and higher revision rates 3
• Avoid excessive flexion and internal rotation of the non-operative hip during surgical positioning 6
• Be cautious with cement usage in elderly patients due to risk of bone cement implantation syndrome 6