Management of Delayed Union
Diagnostic Approach
- MRI is the preferred imaging modality for diagnosing delayed union due to its high sensitivity and specificity in detecting stress injuries and assessing the healing status of bone 1, 2
- CT scanning without contrast can provide detailed structural information about the bone architecture and is useful for surgical planning 1
- Radiographs have limited sensitivity (30-70%) but should be the initial imaging study; follow-up radiographs in 10-14 days may show progression of healing 2
- Bone scintigraphy with SPECT or SPECT/CT can be used but is less specific than MRI and often requires supplemental imaging for conclusive diagnosis 1
Management Options
Mechanical Stabilization
- Definitive osteosynthesis of long-bone fractures is recommended as first-line treatment to prevent complications and promote healing 3
- Intramedullary nailing is preferred for long bone fractures 4
- Plate osteosynthesis is a surgical fixation option 3
- External fixation is particularly useful in a damage control setting 3
- Cross-union technique can be considered for challenging cases with promising initial results (100% union rate) 4, 5
Biological Enhancement
- Autogenous bone grafting is the gold standard biological enhancement technique 4, 5
- Vascularized fibular grafts (VFG) can be considered for complex cases with a reported 88.2% final union rate 4
- Low-intensity pulsed ultrasound stimulation may be used, though evidence for its effectiveness is inconclusive 5
- Bisphosphonates have been used in some protocols, but there is no consensus on their effectiveness for delayed union 5
Special Considerations
High-Risk Fractures
- Certain fractures are considered high risk for delayed union or nonunion and require more aggressive management, including anterior tibial diaphysis, lateral femoral neck and femoral head, navicular, fifth metatarsal base, proximal second metatarsal, medial malleolus, tibial hallux sesamoid, and talus 1
Timing of Intervention
- Early surgical stabilization of long bone fractures (within 24 hours) is associated with decreased incidence of complications 3
- The cross-union technique should be considered in younger patients or those with high-risk anatomical features for refracture 4