Nonunion of Fractures

  • Presence of a postfracture defect in a long bone beyond a reasonable expected healing date, or if no radiographic progression of healing is noted
  • If internal fixation is used to stabilize a fracture, a race exists between fracture healing and hardware failure.
  • Children, because of their active healing potential, rarely develop a nonunion unless other predisposing conditions are present.
  • Classification:
    • Atrophic nonunion:
      • Often poor blood supply
      • When visualized on radiographs, often show poor bone quality with tapered edges
      • Often occur in osteoporotic bone
    • Hypertrophic nonunions:
      • Good blood supply
      • Most go on to heal if adequate stabilization can be achieved.


  • The incidence depends on the fracture type.
    • 13% of tibial fractures
    • 4-11% of clavicle fractures, depending on location
    • Tibial shaft, femoral neck, and scaphoid fractures are at high risk for nonunion because they have a more tenuous blood supply than other bones, which often is damaged with the injury.
Risk Factors
  • Poor nutritional status
  • Poor bone quantity and quality
  • Suppressed immune system
  • Presence of bone infection may contribute to development of a nonunion.
  • Smoking
  • Poor soft-tissue envelope
  • Vascular compromise
  • NSAID use
  • Open fractures
  • Poor fracture reduction
  • Distal tibia fractures
  • Injury-related causes include segmental bone loss, extensive soft-tissue damage, and loss of adequate blood supply.
  • Treatment-related factors include quality of reduction, amount of distraction, and length of immobilization.
  • Inadequate fracture stabilization is a common cause of fracture nonunion.


Signs and Symptoms
  • Patients have a history of a fracture that continues to be painful.
  • The patient may have broken hardware.
  • Pain often occurs after use of the limb.
Physical Exam
  • Patients have continued tenderness at the fracture site.
  • Motion of the bony fragments may or may not be evident.
  • Radiography:
    • Plain AP and lateral radiographs, to determine the presence of callus formation
    • Serial radiographs, to ensure callus progression
  • CT:
    • Excellent at revealing nonunion
    • In many fractures, the fracture plane is difficult to see on plain radiographs because of overlap of the bone fragments.
  • Bone scans, to help determine whether increased blood flow and subsequently increased bone turnover is present at the fracture site
  • MRI is useful when hardware is not present.
Pathological Findings
  • Thick fibrous tissue with areas of uncalcified callus formation
  • A synovial pseudarthrosis or false joint may develop with excessive motion.
Differential Diagnosis
  • Delayed union, characterized by some tenderness and motion at the fracture site with variable amounts of callus present after a period in which most fractures would be healed clinically
  • Painful hardware
  • Posttraumatic arthritis

Treatment for Nonunion of Fractures in Singapore

General Measures
  • Most nonunions are treated with surgical intervention.
  • Aggressive treatment of delayed union can help prevent nonunion and hardware breakage.
  • Nonoperative interventions:
    • Bone stimulators (electrical or ultrasound)
    • Smoking cessation
    • Discontinuation of NSAIDs
    • Use of weightbearing casts or functional braces
  • Surgical treatment of nonunions is determined by type of host, soft-tissue coverage, precise location of the nonunion, type of nonunion, and previous fracture treatment.
  • Patients with severe medical compromise, poor soft-tissue coverage, or poor vascular supply may be candidates for amputation.
  • Hypertrophic nonunion should be treated with rigid fixation of the nonunion, which may require revision of the internal fixation.
  • Nonunion of long-bone fractures with intramedullary nails may be treated with nail dynamization or exchange nailing.
    • Reaming the canal provides local bone graft and allows for placement of a larger diameter nail.
  • Bypass or wave plating allows for fixation and bone grafting (7).
  • For tibial nonunions, bracing may be combined with fibular osteotomy.
  • Well-stabilized atrophic nonunions are treated with bone grafting.
    • Bone graft may be autograft, allograft, or synthetic.
    • The fracture nonunion should be exposed and curetted, and the bone ends should be burred back to bleeding, viable bone.
    • Bone graft material then is packed into the nonunion.
    • The use of bone morphogenic protein 2 recently has been approved for tibial nonunion treatment.
    • The optimal bone graft material or bone morphogenic protein is unknown.
      • Factors to consider with the use of autograft include the need for a 2nd incision and the relative quality of the patient’s bone.
      • Some patients may not want to have a 2nd incision with its risk of pain or infection.
  • Femoral neck nonunions may be treated with realignment osteotomy or joint replacement.
  • Infected nonunion:
    • Treatment is challenging and requires debridement of the infection, fracture stabilization, removal of dead space, and soft-tissue coverage.
    • Plastic surgery reconstruction may be necessary, and multiple surgeries often are necessary.
  • Large bone defects may be managed with bone transport via an external fixation and the Ilizarov method.


  • 90% of nonunions are treated successfully with 1 surgery.
  • In 80% of nonunions, limb length and alignment are restored.
  • If infection is present, often >1 surgery is required.
  • Infection and osteomyelitis
  • Hardware failure
  • Continued nonunion
  • Pain
  • Malunion
  • Joint stiffness
  • Pain and infection at the bone graft donor site
Patient Monitoring
Serial radiographs are obtained once a month, to assess the development of callus.


733.82 Nonunion fracture
Patient Teaching
Strict adherence to the recommendations of the orthopaedic surgeon regarding activity and care of the fracture may reduce the likelihood of developing a nonunion, particularly with problematic fractures.
Excellent reduction of fractures, smoking cessation, and aggressive treatment of delayed unions decrease nonunion rates.


Q: How long does a nonunion take to heal?
A: 90% of nonunions are treated successfully with 1 surgical intervention, and healing occurs over a 3-4-month period. Full rehabilitation with muscle strengthening takes longer, because the patient often is debilitated before treatment.


If you would like an appointment / review with our fractures specialist in Singapore, the best way is to call +65 6664 8135 or click here to book an appointment at the clinic. If you would like to speak to one of our clinicians first about e.g. how common are non union fractures, nonunion fracture surgery, bone grafts, hypertrophic nonunion etc, then please contact or SMS/WhatsApp to +65 6664 8135.

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