What are the considerations for bone grafting in the legs?

Bone Grafting Considerations for the Legs

For severe limb trauma in the legs, the cross-union technique is recommended as the optimal bone grafting approach due to its superior 100% union rate, shortest mean union time (4.5 months), and lowest refracture rate (22.5%) compared to other methods. 1

Surgical Approach Selection

The surgical approach for bone grafting in the legs should follow this algorithm:

1. Assess patient stability and injury severity:

   • Prioritize patient survival over limb salvage in unstable patients 1
   • Consider damage control orthopedics (DCO) for patients with hemorrhagic shock 1

2. Evaluate the cumulative injury burden 1:

   • Soft tissue damage
   • Vascular injury
   • Bone defects
   • Joint involvement

3. Select appropriate bone grafting technique based on injury pattern:

For Congenital Pseudarthrosis of the Tibia (CPT)

• Cross-union technique: First-line choice with 100% union rate and 22.5% refracture rate 1
• Combined Ilizarov fixator with intramedullary fixation: Second-line option with 84% primary union rate and 93.3% final union rate 1
• Vascularized fibular graft (VFG): Reserve for cases where other techniques have failed or when a single-stage procedure is necessary in an unscarred field 1

For Prosthetic Joint Infection (PJI)

• Two-stage exchange: Preferred approach for patients who can undergo multiple surgeries 1
• One-stage exchange: Consider for hip arthroplasty infections when pathogens are known and susceptible to oral antibiotics with good bioavailability; however, bone grafting may increase risk of failure 1

Timing of Bone Grafting

The timing of bone grafting is critical for successful outcomes:

• Acute trauma: Consider DCO with temporary stabilization when definitive osteosynthesis is not anticipated in the next 24-36 hours 1
• Infected cases: Complete eradication of infection before bone grafting 2
• CPT in children: Operate when patients are over 2 years old 1

Material Selection

Material selection should be based on the specific requirements of the defect:

• Autograft: Gold standard with osteogenic, osteoinductive, and osteoconductive properties 2, 3, 4
• Harvest sites for autograft (in order of preference):
  1. Ipsilateral proximal tibia
  2. Distal tibia
  3. Calcaneus
  4. Iliac crest (higher complication rate) 5

Special Considerations

For Severe Limb Trauma

• No single gravity criterion mandates amputation 1
• Consider limb salvage in hemodynamically stable patients 1
• Screen for psychosocial risk factors (depression, PTSD, anxiety) that may affect outcomes 1

For Bone Grafting in CPT

• Complete excision of the pseudarthrosis site is essential 1
• Use sufficient autogenous bone graft 1
• Consider external fixator with intramedullary fixation 1

Potential Complications

• Refracture: Highest with VFG (45%) and lowest with cross-union technique (22.5%) 1
• Non-union: Ranges from 6% with combined Ilizarov/intramedullary fixation to 7.3% with VFG 1
• Donor site morbidity: Particularly with VFG, including sensory/motor weakness and valgus ankle deformity 1

Follow-up Considerations

• Monitor for refracture, especially in the first year after surgery
• Assess for limb length discrepancy
• Evaluate functional outcomes and need for additional interventions

The cross-union technique represents a significant advancement in bone grafting for the legs, particularly for CPT, with its superior union rates and lower complication profile compared to traditional approaches. However, the technique selection must be tailored based on the specific injury pattern, patient factors, and surgeon expertise.