What Is Fracture Nonunion?
Fracture nonunion describes failure of a fracture to demonstrate satisfactory progression toward union according to the clinical, radiographic and mechanical context.
Although time from injury is part of the assessment, nonunion should not be diagnosed from one arbitrary time threshold alone.
Evaluation considers:
- Time since injury
- Fracture type
- Serial imaging
- Pain
- Stability
- Previous surgery
- Biological factors
Why Do Fractures Fail to Heal?
Causes can be broadly mechanical, biological or infectious.
Mechanical and biological problems frequently coexist.
Common contributing factors include:
- Inadequate stability
- Excessive motion
- Poor blood supply
- Bone loss
- Infection
- Severe soft-tissue injury
- Open fracture
- Smoking
- Certain medical factors
- Multiple previous operations
More than one factor is often present.
What Is an Atrophic Nonunion?
An atrophic nonunion demonstrates limited biological healing activity.
Potential contributors can include:
- Poor blood supply
- Severe soft-tissue injury
- Bone loss
- Infection
- Biological compromise
Treatment often requires attention to both biology and mechanical stability.
What Is a Hypertrophic Nonunion?
A hypertrophic nonunion demonstrates biological activity but insufficient mechanical stability.
Radiographs may show abundant callus without successful bridging.
Improving stability can be a major component of treatment.
How Is Nonunion Evaluated?
Evaluation may include:
- Injury history
- Previous operations
- Examination
- X-rays
- CT in selected cases
- Blood tests
- Infection assessment
- Review of implants
- Assessment of limb alignment
- Review of smoking and medical factors
The treatment plan should address the reason for failure.
Why Must Infection Be Considered?
Occult infection should remain part of the differential diagnosis in selected nonunions, particularly after previous surgery or open fracture.
When clinically relevant, assessment can include:
- Clinical history
- Examination
- ESR/CRP or other inflammatory markers where appropriate
- Previous microbiology
- Imaging where useful
- Multiple separately collected deep tissue samples when surgery is undertaken
Normal inflammatory markers do not absolutely exclude fracture-related infection.
Unexpected infection can significantly change the reconstructive strategy.
What Role Does Stability Play?
Fracture healing requires an appropriate mechanical environment.
Too much motion can prevent bridging and maturation of bone.
Existing fixation should therefore be assessed for:
- Stability
- Alignment
- Implant failure
- Construct design
- Ability to support healing
Simply adding bone graft without correcting major mechanical instability may not be sufficient.
What Role Does Biology Play?
Healing requires:
- Blood supply
- Viable bone
- Appropriate soft-tissue coverage
- Biological healing capacity
Surgery May Sometimes Include:
- Debridement of nonviable tissue
- Bone grafting
- Bone transport
- Other biological reconstruction
The technique depends on the defect.
What Is Bone Grafting?
Bone graft can be used to improve the biological environment or fill selected defects.
Sources and techniques vary.
The need for grafting depends on:
- Type of nonunion
- Bone defect
- Biology
- Stability
- Infection status
Bone graft is not a substitute for adequate mechanical stability or infection control.
What If There Is Bone Loss?
Segmental or significant bone loss can require advanced reconstruction.
Options can include:
- Structural grafting
- Bone transport
- Induced membrane techniques
- Specialized fixation
- Other reconstruction
The strategy depends on defect size, location, infection and soft tissues.
What If the Fixation Has Failed?
Broken fixation should prompt assessment of why the construct failed.
Implant breakage is often a consequence of an unresolved mechanical, biological or infectious problem rather than the diagnosis itself.
Revision may require:
- Restoring stability
- Correcting alignment
- Revising fixation
- Addressing bone defects
- Optimizing biology
- Treating infection when present
Implant removal is not automatically required solely because previous hardware exists.
What Is Malalignment?
A fracture can fail to heal in an abnormal position or may heal with deformity.
Relevant issues can include:
- Angulation
- Rotation
- Shortening
- Mechanical-axis disturbance
Correction may be required when deformity affects function or reconstruction.
How Is Nonunion Treated?
Treatment is individualized and may include:
- Revision internal fixation
- Exchange nailing
- Plate fixation
- Bone grafting
- Debridement
- Correction of deformity
- Infection treatment
- Bone-defect reconstruction
No single procedure is correct for every nonunion.
How Long Does Nonunion Treatment Take?
Healing can take months and sometimes longer.
The timeline depends on:
- Bone involved
- Type of nonunion
- Infection
- Defect size
- Stability
- Soft tissues
- Smoking
- General health
Complex cases may require staged surgery.
How Do I Know If My Fracture Is Not Healing?
Persistent pain, lack of radiographic progression or fixation problems may raise concern, but diagnosis requires clinical and imaging assessment.
Does Every Nonunion Need Surgery?
No. Treatment depends on stability, symptoms, biology and fracture characteristics.
Can a Fracture Fail to Heal Because of Infection?
Yes.
Does Bone Graft Guarantee Healing?
No. Stability, biology and infection control must all be addressed.
Can Smoking Affect Fracture Healing?
Yes. Smoking is associated with impaired bone healing and increased complications.
Can Nonunion Be Treated After Several Previous Operations?
Yes, but reconstruction becomes more complex and requires careful review of previous procedures and remaining biology.
Written and medically reviewed by: Dr. Yousef Abuodeh Consultant Orthopedic Surgeon Last medically reviewed: September 2, 2026