A non union is an arrest in the fracture repair process.

A delayed union is defined as a failure to reach bony union by 6 months post-injury. This also includes fractures that are taking longer than expected to heal (i.e. distal radial fractures). Large segmental defects should be considered functional non-unions.

Risk factors: 

  • Smoking
  • Infection
  • Vitamin D deficiency.
  • Thyroid imbalance:
  • Occult infection: up to 30% of non-union patients will have unexpected positive cultures;

Diagnosis –


CT scan

Types of nonunion

  1. Septic nonunion
  2. Pseudoarthrosis
  3. Hypertrophic nonunion
    • Caused by inadequate immobilization with adequate blood supply
    • Typically heal once mechanical stability is improved
  4. Atrophic nonunion
    • Caused by inadequate immobilization and inadequate blood supply
  5. Oligotrophic nonunion
    • Produced by inadequate reduction with fracture fragment displacement


Pharmacologic treatment – certain drugs like calcium, vitamin D, bisphosphonates and recombinant parathyroid hormone.

Treatment of infection if any

Bone grafting

Change of implant and repeat fracture fixation.