What are the management options for delayed union?

Management of Delayed Union

The most effective management of delayed union involves a combination of surgical stabilization and biological enhancement techniques, with MRI being the preferred diagnostic imaging modality to guide treatment decisions. 1

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
• 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 1
• 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 1
• For unstable fractures or those at high risk for nonunion, surgical fixation options include:
  • Intramedullary nailing (preferred for long bone fractures) 1
  • Plate osteosynthesis 1
  • External fixation (particularly useful in a damage control setting) 1
  • Cross-union technique (creating a fusion between tibia and fibula) for challenging cases with promising initial results (100% union rate) 1

Biological Enhancement

• Autogenous bone grafting is the gold standard biological enhancement technique 1
• Vascularized fibular grafts (VFG) can be considered for complex cases with a reported 88.2% final union rate, though refracture rates are high (45%) 1
• Bone marrow aspirate containing mesenchymal stem cells can stimulate healing in delayed union cases 2
• Weekly teriparatide (56.5 mg) injections have shown effectiveness in promoting bone healing within 4 weeks of initiation in delayed union cases 3

Adjunctive Therapies

• Pulsed electromagnetic field therapy may be beneficial for certain delayed unions, particularly in the tibia, with some studies showing successful healing after 3-6 months of treatment 4
• Low-intensity pulsed ultrasound stimulation may be used, though evidence for its effectiveness is inconclusive 1
• Bisphosphonates have been used in some protocols, but there is no consensus on their effectiveness for delayed union 1

Special Considerations

High-Risk Fractures

• Certain fractures are considered high risk for delayed union or nonunion and require more aggressive management:
  • Anterior tibial diaphysis 1, 4
  • Lateral femoral neck and femoral head 1
  • Navicular, fifth metatarsal base, proximal second metatarsal 1
  • 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 1
• For established delayed unions, intervention should not be delayed beyond 3-6 months if no signs of progressive healing are observed 4
• The cross-union technique should be considered in younger patients or those with high-risk anatomical features for refracture 1

Pitfalls and Caveats

• Failure to identify and address both mechanical and biological factors contributing to delayed union can lead to treatment failure 2, 5
• Inadequate stabilization is a common cause of persistent delayed union 5
• Patient factors such as smoking, diabetes, and poor nutritional status must be addressed for optimal outcomes 2
• Posterior approaches for cervical spine pseudarthrosis have shown higher fusion rates (94-100%) compared to anterior approaches (45-88%) 1
• Overemphasis on radiographic findings without correlation to clinical symptoms may lead to unnecessary interventions 1