What is the recommended management for a scaphoid fracture non‑union?

Scaphoid Fracture Non-Union Management

Surgical intervention is the definitive treatment for scaphoid non-union, with the specific technique determined by fracture location, presence of avascular necrosis, and degree of bone loss.

Surgical Approach Algorithm

For Waist and Proximal Pole Non-Unions:

• Plate fixation is superior to screw fixation alone, particularly for waist (100% vs 64% union rate) and proximal pole locations (100% vs 33% union rate) 1
• Vascularized bone grafting shows superior outcomes when avascular necrosis is present or blood supply is compromised 2
• Non-vascularized bone grafting is effective in early-stage non-union with minimal bone resorption and intact vascularity 2

For Distal Pole Non-Unions:

• Both screw and plate fixation show comparable high union rates (87% vs 100%) 1
• Choice depends on surgeon expertise and specific patient factors 1

Emerging Technique Considerations:

• Dual screw fixation without bone graft is gaining momentum as first-line treatment for non-unions with or without humpback deformity and cyst formation 3
• Arthroscopic-assisted reduction with metaphyseal core decompression of distal radius shows promise in young, non-smoking patients, particularly for unstable stages and bone defects >10mm 4

Critical Decision Points

Assess these factors systematically:

1. Vascularity status: Use MRI with contrast (sensitivity 66%, specificity improved over non-contrast) or dual-energy CT with IV contrast (sensitivity 100%, specificity 94%) to evaluate proximal pole viability 5

2. Anatomical location:

   • Proximal pole: Highest risk, requires aggressive approach with plate fixation or vascularized graft
   • Waist (most common at 52.5%): Plate fixation preferred 1, 6
   • Distal: Either fixation method acceptable

3. Bone loss extent:

   • Minimal resorption: Non-vascularized graft acceptable
   • Significant loss or avascular necrosis: Vascularized bone grafting mandatory 2

4. Sclerosis and fragment viability:

   • Significant sclerosis or absent punctate bleeding: Poor candidate for minimally invasive approaches 4

Imaging Protocol

CT without contrast is the primary modality for assessing trabecular bridging, nonunion confirmation, malunion, and surgical planning with 3-D reconstruction 5

Add contrast-enhanced imaging (MRI or dual-energy CT) when evaluating for osteonecrosis, particularly in proximal pole fractures 5

Common Pitfalls

• Underestimating proximal pole complexity: These have the highest failure rates (67% non-union with screw alone) and require more aggressive fixation 1
• Delayed referral: Non-union rates as high as 82.8% occur when cases are not aggressively managed with early CT follow-up at 3 months 6
• Inadequate fixation selection: Overall union rates range 70-95%, with higher success in appropriately matched technique to lesion characteristics 2
• Ignoring vascular status: Attempting non-vascularized approaches in avascular bone leads to persistent non-union

Contraindications to Minimally Invasive Approaches

Do not use arthroscopic or percutaneous techniques when:

• Complete absence of punctate bleeding in proximal pole
• Significant sclerosis present
• Very small proximal fragment size 4

The evidence strongly favors plate fixation over traditional screw fixation for waist and proximal pole non-unions, with vascularized bone grafting reserved for cases with confirmed avascularity 1, 2.