ConditionBones, joints & muscles
Nonunion (Failed Bone Healing)
A nonunion is a broken bone that has stopped healing, usually defined as no progress on X-rays for 3 months or a fracture not healed by about 6 to 9 months. It causes ongoing pain, swelling or abnormal movement at the break. Risk is higher with smoking, diabetes, poor blood supply to the bone, infection, unstable fixation and certain bones such as the scaphoid and shin. Most nonunions can be healed with surgery to stabilize the bone and add bone graft, sometimes with bone stimulation.
Also called: Bone nonunion, failed fracture healing, ununited fracture, pseudarthrosis
At a glance
- What it is
- A fracture that has not healed and is unlikely to heal without further treatment.
- Signs
- Persistent pain, swelling, tenderness or abnormal movement at the break months after injury.
- Risk factors
- Smoking, diabetes, poor nutrition, infection, unstable fixation, poor blood supply, NSAID overuse, certain bones.
- Diagnosis
- X-rays over time, CT scan, blood tests for infection and metabolic causes.
- Treatment
- Stabilizing surgery, bone grafting, treating infection, bone stimulation, and addressing risk factors.
When to get help
See a doctor within a day or two
- Fever, increasing redness, swelling or drainage from a wound over a healing fracture (possible infection)
- Sudden increase in pain, deformity or a click at a fracture site, or broken hardware
- Numbness, coldness or color change in the limb
Book a routine appointment
- Pain or movement at a fracture site more than 3 months after injury
- A fracture that feels like it is "giving" when you put weight on it
- Persistent wrist pain on the thumb side after a fall, even with normal initial X-rays (possible scaphoid fracture)
How bones heal and why they sometimes do not
Normal healing needs three things: stability, a good blood supply and the right biology (cells, growth signals and nutrients). A soft callus forms within weeks, hardens into bone over months, then remodels. Most fractures heal in 6 to 12 weeks, though larger bones take longer.
When one or more of these factors fails, healing slows (delayed union) or stops (nonunion).
Types of nonunion
| Type | Description | Main problem | Typical treatment |
|---|---|---|---|
| Hypertrophic | Lots of callus but no bridging, "elephant foot" on X-ray | Too much movement | Rigid stabilization |
| Atrophic | Little or no callus, bone ends thin | Poor biology or blood supply | Bone graft plus stabilization |
| Oligotrophic | Some callus, not enough | Mixed | Stabilization, often graft |
| Infected | Nonunion with infection | Infection | Remove infected bone, treat infection, reconstruct |
| Pseudarthrosis | A false joint with fluid-filled space | Long-standing motion | Surgery |
Risk factors
Patient factors
- smoking and nicotine use: one of the strongest risk factors
- diabetes
- poor nutrition, low protein, vitamin D deficiency
- older age
- obesity
- some medicines: long-term steroids and, possibly, prolonged high-dose NSAIDs
- thyroid and other hormone problems
- heavy alcohol use
Injury factors
- high-energy injuries with extensive soft tissue damage
- open fractures
- bone loss
- infection, including osteomyelitis
Location
Some bones have a vulnerable blood supply:
- scaphoid (wrist)
- tibia (shin)
- fifth metatarsal (Jones fracture)
- femoral neck (hip)
- clavicle (in some displaced fractures)
Treatment factors
- not enough stability, or too rigid fixation in some cases
- gaps between bone ends
- early overloading
Symptoms
- persistent pain at the fracture site, often with weight bearing or use
- swelling and tenderness
- abnormal movement, clicking or a feeling of instability
- deformity
- difficulty bearing weight or using the limb
- if infected: redness, warmth, wound drainage, fever
Diagnosis
- examination for tenderness and abnormal movement
- serial X-rays comparing healing over time
- CT scan: the best way to see whether bone has bridged the gap
- MRI for blood supply problems (such as in the scaphoid) or infection
- blood tests: inflammatory markers (CRP, ESR), blood count, vitamin D, calcium, thyroid, blood sugar
- biopsy or cultures during surgery if infection is suspected
Treatment
Address risk factors
- stop smoking and nicotine products
- control diabetes
- correct vitamin D and nutrition
- review medicines
Non-surgical options
- bone stimulators: low-intensity pulsed ultrasound or electrical stimulation, used in selected nonunions with good alignment and stability, with mixed evidence
- bracing and modified weight bearing
Surgery
- revision fixation: new or larger plates, rods (nails) or external fixators to improve stability
- bone grafting: the patient's own bone (often from the pelvis) is the gold standard. Donor bone and bone graft substitutes are alternatives
- biological agents: bone morphogenetic proteins in selected cases
- infected nonunion: removal of dead and infected bone, antibiotics, and staged reconstruction, sometimes with bone transport techniques
Most nonunions heal after appropriate surgery, often within 3 to 6 months.
Prevention
- follow weight-bearing and immobilization instructions
- stop smoking during fracture healing
- eat enough protein, calcium and vitamin D
- attend follow-up X-rays
- seek review for persistent pain beyond the expected healing time
Frequently asked questions
What is a nonunion fracture?
A nonunion is a broken bone that has stopped healing. It is usually diagnosed when there is no progress on X-rays for several months or the fracture has not healed by 6 to 9 months.
What causes a bone not to heal?
Common causes include smoking, diabetes, poor nutrition, low vitamin D, infection, inadequate stability of the fracture, poor blood supply to the bone, and high-energy injuries. Some bones, like the scaphoid and shin, are especially prone.
What are the signs of a nonunion?
Signs include ongoing pain at the fracture site months after injury, swelling, tenderness, a feeling of movement or instability, and difficulty bearing weight. X-rays or a CT scan confirm it.
How is a nonunion treated?
Treatment usually involves surgery to stabilize the bone with plates, rods or an external frame, often with bone grafting to stimulate healing. Infection is treated if present. Bone stimulators help in selected cases. Stopping smoking is essential.
How long does it take for a nonunion to heal after surgery?
Most nonunions heal within 3 to 6 months after surgery, though some take longer, especially infected or atrophic nonunions. Regular X-rays track progress.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Orthopaedic Surgeons (OrthoInfo): Nonunions
- Orthopaedic Trauma Association: Nonunion resources
- AO Foundation: Nonunion management principles
- NHS: Broken bones (recovery)
- MedlinePlus: Fractures