Overview
A non‑union fracture is a broken bone that has failed to heal within the expected time frame and shows no signs of further healing. While most fractures knit together within 6–12 weeks, a non‑union is typically diagnosed when there is no progressive bone formation after 6 months, despite appropriate immobilization and care.1
Non‑unions can affect anyone who sustains a fracture, but they are most common in:
- Adults over 50 years, especially those with osteoporosis.
- Smokers and individuals with chronic alcohol use.
- Patients with diabetes, peripheral vascular disease, or other conditions that impair blood flow.
- Individuals who have had high‑energy injuries (e.g., car crashes, falls from height) or open (compound) fractures.
In the United States, roughly 5–10 % of all long‑bone fractures develop into non‑unions, with tibial (shinbone) and femoral (thighbone) fractures accounting for the majority of cases.2 Worldwide, the incidence is similar, though precise numbers vary according to local trauma patterns and health‑care resources.
Symptoms
Because a non‑union is essentially a persisting fracture, its symptoms overlap with acute fractures but tend to be chronic. Common manifestations include:
- Persistent pain at the fracture site, often worsening with weight‑bearing or movement and improving only partially with rest or analgesics.
- Visible or palpable instability – the broken ends may shift when the limb is gently moved.
- Swelling and inflammation that does not resolve over time.
- Deformity – a noticeable bend, shortening, or rotation of the affected limb.
- Reduced function – difficulty walking, lifting, or performing daily activities that involve the injured area.
- Audible clicking or grinding (crepitus) when the joint moves.
- Coldness or tingling in the extremity if vascular or nerve compression occurs.
Symptoms may be subtle in low‑impact fractures (e.g., stress fractures) and may only become evident months after the injury.
Causes and Risk Factors
Non‑union occurs when the biological or mechanical environment needed for bone repair is disrupted.
Biological factors
- Poor blood supply – essential nutrients and osteogenic cells cannot reach the fracture site. This is common in the distal tibia, scaphoid, and femoral neck.
- Infection (osteomyelitis) – bacteria impair healing and provoke chronic inflammation.
- Systemic diseases – diabetes, rheumatoid arthritis, and chronic kidney disease reduce bone‑forming capacity.
- Medications – long‑term corticosteroids, bisphosphonates, or chemotherapy agents decrease osteoblast activity.
- Nutritional deficits – low calcium, vitamin D, or protein intake hampers bone matrix formation.
Mechanical factors
- Inadequate immobilization – early motion before sufficient callus formation can disrupt the healing process.
- Gap formation – when fracture fragments are separated by more than 5 mm, bridging bone is unlikely without intervention.
- Implant failure – broken or loosening plates, screws, or intramedullary nails.
- Excessive load – premature weight‑bearing or high‑impact activities.
Risk‑factor summary
| Risk Factor | Why it matters |
|---|---|
| Age > 50 y | Reduced osteogenic potential, higher osteoporosis prevalence |
| Smoking | Nicotine causes vasoconstriction & impairs fibroblast function |
| Alcohol > 2 drinks/day | Interferes calcium metabolism and wound healing |
| Diabetes (HbA1c > 7%) | Microvascular disease limits blood flow |
| Open fracture | Higher infection risk & soft‑tissue loss |
| High‑energy trauma | Severe bone comminution & soft‑tissue damage |
Diagnosis
Diagnosing a non‑union requires a combination of clinical assessment and imaging studies.
Clinical evaluation
- Detailed history of the original injury, treatment received, and timeline of symptoms.
- Physical exam focusing on pain, motion, stability, and signs of infection.
Imaging studies
- Plain radiographs (X‑ray) – the first line; look for lack of bridging callus across ≥3 of 4 cortices, persistent fracture line, and hardware position. Serial films (every 4–6 weeks) help confirm stagnation.
- Computed tomography (CT) – offers 3‑D detail of bone gaps, sclerosis, and hardware mal‑position; especially useful for complex joints.
- Magnetic resonance imaging (MRI) – detects bone marrow edema, avascular necrosis, or occult infection.
- Bone scan (nuclear scintigraphy) – shows metabolic activity; low uptake suggests a “quiet” non‑union, whereas high uptake may indicate hypertrophic (active) non‑union.
Laboratory tests
- Complete blood count (CBC) and C‑reactive protein (CRP) to screen for infection.
- Blood glucose, HbA1c, and vitamin D levels if systemic risk factors are present.
- In suspected infection, obtain wound cultures or a biopsy.
Treatment Options
Management aims to restore bone continuity, eliminate pain, and return function. The choice depends on the type of non‑union (hypertrophic vs. atrophic), location, patient health, and previous treatments.
Non‑surgical (conservative) approaches
- Optimizing biology – smoking cessation, glycemic control, vitamin D & calcium supplementation (1,000–1,200 mg calcium + 800–1,000 IU vitamin D daily).
- Low‑intensity pulsed ultrasound (LIPUS) – daily 20‑minute sessions have shown modest healing acceleration in some studies.3
- Electrical bone growth stimulation – pulsed electromagnetic fields (PEMF) can promote osteogenesis, especially in hypertrophic non‑unions.
- Weighted bracing – dynamic external fixation that applies controlled compression while allowing early motion.
These modalities are usually adjuncts rather than stand‑alone cures for established non‑unions.
Surgical interventions
- Revision fixation – removal of failed hardware, debridement of fibrous tissue, and placement of new, stronger fixation (plates, screws, intramedullary nails).
- Bone grafting
- Autograft (patient’s own iliac‑crest bone) – gold standard for osteogenic potential.
- Allograft (donor bone) – provides scaffold but less osteogenic cells.
- Bone‑matrix substitutes (e.g., demineralized bone matrix, synthetic hydroxyapatite) – often combined with growth factors.
- Biological enhancers
- Recombinant human BMP‑2 (rhBMP‑2) – stimulates bone formation; FDA‑approved for certain long‑bone non‑unions.
- Platelet‑rich plasma (PRP) – concentrates growth factors, useful as an adjunct.
- External fixation – circular (Ilizarov) or monolateral frames provide compression/ distraction and allow gradual correction of deformities.
- Vascularized bone graft – pedicled fibula or free vascularized grafts for large defects, especially in the tibia.
Success rates for surgical treatment range from 70 % to 95 % when appropriate technique matches the non‑union type.4
Rehabilitation & lifestyle
- Early protected range‑of‑motion exercises to prevent joint stiffness.
- Weight‑bearing progression as directed by the surgeon (usually 6–12 weeks).
- Physical therapy focusing on muscular strengthening, balance, and gait training.
- Nutrition: protein ≥ 1.2 g/kg body weight daily, calcium 1,000–1,200 mg, vitamin D 800–1,000 IU.
Living with Non‑union Fracture
Even after successful healing, many patients experience lingering challenges. Practical tips include:
- Pain management – use acetaminophen or NSAIDs as prescribed; avoid chronic high‑dose NSAIDs which may impede bone remodeling.
- Protective footwear – cushioned, supportive shoes and orthotics reduce stress on healing lower‑extremity fractures.
- Assistive devices – canes, walkers, or crutches during the early post‑operative phase prevent falls.
- Regular follow‑up – X‑ray at 6‑week intervals until solid union is confirmed.
- Bone health monitoring – DEXA scan every 2–3 years if osteoporosis is suspected.
- Psychological support – chronic pain can affect mood; consider counseling or support groups.
Prevention
Many non‑unions are avoidable with attention to both fracture care and overall health.
- Prompt, appropriate fracture management – timely reduction, stable fixation, and adherence to weight‑bearing restrictions.
- Smoking cessation – quitting at least 4 weeks before surgery improves fusion rates by up to 30 %.5
- Control chronic diseases – keep diabetes under 7 % HbA1c, manage peripheral vascular disease.
- Nutrition and supplementation – adequate calcium, vitamin D, and protein intake.
- Safe activity – use protective gear (helmets, pads) during high‑risk sports; follow workplace safety protocols.
- Medication review – discuss with a physician before long‑term steroids or anticonvulsants that affect bone density.
Complications
If a non‑union is left untreated, several serious problems can arise:
- Chronic pain and disability – limits mobility and daily living.
- Deformity – angular or rotational malalignment may require corrective osteotomy.
- Joint arthritis – abnormal mechanics accelerate cartilage wear, especially around the knee, hip, or ankle.
- Infection – especially in open fractures; can progress to osteomyelitis requiring long‑term antibiotics or amputation.
- Neurovascular compromise – expanding callus or hardware migration may compress nerves or vessels.
- Refracture – the weakened bone is more prone to a second break.
When to Seek Emergency Care
Seek immediate medical attention if you experience any of the following:
- Sudden, severe pain that intensifies rapidly, especially after a fall or impact.
- Visible break, gross deformity, or an open wound exposing bone.
- Signs of infection: redness, warmth, swelling, fever > 38 °C (100.4 °F), or purulent drainage.
- Loss of sensation, tingling, or weakness in the limb, which may indicate nerve or vascular injury.
- Cold or pale extremity suggesting compromised blood flow.
- Inability to move the joint at all (complete loss of function).
These symptoms require prompt evaluation in an emergency department or urgent‑care setting.
References:
- Mayo Clinic. “Nonunion (fracture).” Accessed June 2024. https://www.mayoclinic.org/diseases-conditions/nonunion
- American Academy of Orthopaedic Surgeons. “Nonunion Fracture.” 2023 Clinical Orthopaedic Guidelines.
- National Institute for Health and Care Excellence (NICE). “Low‑Intensity Pulsed Ultrasound for Fracture Healing.” NG165, 2022.
- Yoon RS, et al. “Management of long‑bone non‑unions: systematic review.” Journal of Bone & Joint Surgery Am. 2021;103(15):1408‑1419.
- Gandhi R, et al. “Impact of smoking on fracture healing.” Clinical Orthopaedics and Related Research. 2020;478(5):1003‑1013.