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.

Epidemiology

• 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.

• 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

• 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

Miscellaneous

FAQ