Fracture non-union describes the failure of normal fracture healing processes. Solid bone healing will not occur without further treatment intervention.
There is no consensus definition in the radiology or orthopedic literature, however, FDA (USA) defines it as a fracture with a minimum of at least nine months since the initial injury with no signs of healing for the final three months .
There are different types of fracture non-union with various imaging characteristics:
- hypertrophic: abundant callus formation; radiolucent line (unmineralized fibrocartilage) at the nonunion site
- oligotrophic: little or no callus formation; diastasis at the fracture site
- atrophic: bony surfaces partially resorbed; no callus formation; osteopenia; sclerotic avascular bone segments; segmental bone loss
- infected: osteolysis; osteopenia; sclerotic avascular bone segments; segmental bone loss
- synovial pseudarthrosis: variable appearance (hypertrophic, oligotrophic, or atrophic)