Nonunion

Non-Union

Definition

• No clinical or radiographic evidence of healing for 3 months beyond the expected healing time of a given bone, with no signs that the bone will continue towards union.

Risk Factors

Classification

Diagnosis

• High index of suspicion based on risk factors for a given patient.

Clinical Union Indicators

• Pain-free under physiological loading.
• Non-mobile fracture.

X-ray Indicators of Non-Union

• Persistent fracture gap.
• Sclerotic, rounded, or faded bone ends.
• Metalware failure or loosening.
• New deformity.

X-ray Indicators of Union

• Bridging callus and restoration of cortical congruity.
• Obliteration of fracture gaps.
• Bridging trabeculae on 3 out of 4 cortices.
• The most reliable method is the number of cortices bridged.

Additional Diagnostic Tools

• CT Scan: Useful for complex periarticular non-unions.
• Bone Scan: Generally not very useful; may show cold areas in atrophic or synovial non-unions.
• MRI: Good for diagnosing and quantifying infection and for pre-operative planning.

Treatment of Non-Union

• The treatment depends on the type of non-union.

Hypertrophic Non-Union

• Improve the strain environment by lowering strain through interfragmentary compression and rigid fixation.

Infected Non-Union

• The infection must be eradicated before healing can proceed.
• Debride the non-union site back to clean, bleeding bone ends.
• A staged protocol may be required.
• Use external fixation if possible or techniques such as distraction osteogenesis.

Atrophic Non-Union

• Problem due to biology or inadequate compression with rigid, low-strain fixation.
• Debride the non-union site.
• Drill the canals until bone bleeds.
• Use bone grafting.
• Fix rigidly with compression or use techniques such as exchange nailing with grafting.
• The key is to create bleeding surfaces at the non-union site and use bone grafts to promote healing.