nonunion
Failure of bone fracture to heal within the expected timeframe despite adequate treatment.
Full Definition
Nonunion is a complication of fracture healing where the bone fails to heal completely within the expected timeframe, typically defined as six months to one year depending on the bone involved. This condition occurs when the biological and mechanical environment is insufficient to achieve bony union. Contributing factors include infection, inadequate blood supply, excessive motion at the fracture site, smoking, poor nutrition, and certain medications. Nonunions are classified as hypertrophic (with callus formation) or atrophic (without callus formation) and often require surgical intervention including bone grafting, revision fixation, or biologic enhancement.
Usage
Usage note: Distinguish from 'delayed union' (slow healing) and 'malunion' (healed in poor position).
In Context
- "CT scan confirmed atrophic nonunion of the scaphoid waist fracture." — Radiology report
- "The patient developed nonunion requiring revision surgery with bone grafting." — Follow-up clinic note