May 30, 2024

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

Causes of Non-union
Causes of Non-union

Classifications of Non-Union

a. Location

  • Epiphyseal
  • Metaphyseal
  • Diaphyseal

b. Presence and absence of infection

  • Septic
  • Aseptic

c. Biological Reaction

  1. Hypervascular Nonunion
    1. Hypertrophic Nonunion
    2. Horse-hoof Nonunion
    3. Oligotrophic Nonunion
  2. Avascular Nonunion
    1. Torsion wedge Nonunion
    2. Communited Nonunion
    3. Defect Nonunion
    4. 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

Paley classification of nonunion
Paley classification

See also: Scaphoid fractures

See also: Tension band principles

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