Non-Union is defined according to USFDA as ” Established when a minimum of 9 months has elapsed since injury and the fracture shows no visible sign of healing for 3 months”
Absolute Stability
Criteria for absolute stability:
Interfragment motion: <0.15 mm
Strain: < 2%
Fracture gap : < 0.1 mm
If the fracture gap is >0.1 mm, there will be no primary healing there will be Gap Healing
In Gap healing strain is < 2%, gap up to 1 mm is tolerated
Etiology of Nonunion
Classifications of Non-Union
a. Location
- Epiphyseal
- Metaphyseal
- Diaphyseal
b. Presence and absence of infection
- Septic
- Aseptic
c. Biological Reaction
- Hypervascular Nonunion
- Hypertrophic Nonunion
- Horse-hoof Nonunion
- Oligotrophic Nonunion
- Avascular Nonunion
- Torsion wedge Nonunion
- Communited Nonunion
- Defect Nonunion
- Atrophic Nonunion
d. Paley’s classification ( Modification of Ilizarov)
Amount of bone loss:
Type A: < 1 cm bone loss
Type B: > 1 cm bone loss
Type C: Associated with infection
Illustrative Paley’s Classification
See also: Scaphoid fractures
See also: Tension band principles
