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:
- NSAIDS;
- Smoking
- Infection
- Vitamin D deficiency.
- Thyroid imbalance:
- Occult infection: up to 30% of non-union patients will have unexpected positive cultures;
Diagnosis –
Xrays
CT scan
Types of nonunion
- Septic nonunion
- Pseudoarthrosis
- Hypertrophic nonunion
- Caused by inadequate immobilization with adequate blood supply
- Typically heal once mechanical stability is improved
- Atrophic nonunion
- Caused by inadequate immobilization and inadequate blood supply
- Oligotrophic nonunion
- Produced by inadequate reduction with fracture fragment displacement
Treatment
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.