Non-union of bone is the body’s inability to heal a fracture. Commonly used is the FDA definition of non-union that states non-union is fracture that persists for a minimum of nine months without signs of healing for three months. 1

The rate of all fracture non-unions is between 1.9% and 10%. Variable rates of non-union exist depending on the anatomic region. Femoral shaft non-unions are estimated to be 8% overall with the use of intramedullary nailing. Tibial shaft non-unions occur at a rate of 4.6% after intramedullary nailing. However, there are several discrepancies, as some studies have shown tibia non-union to be as high as 10% to 12% overall. Soft tissue damage negatively impacts the ability to heal bone. Studies of open fractures with extensive soft compromise showed non-unions to be much higher at 16%.

The pathophysiology of a bone non-union is multifactorial 2:

    • Inadequate fracture stabilization and poor blood supply lead to non-union
    • Infection can lea dto non-union and infection eradication needs to occur prior to or at the same time with achieving fracture union
    • Scaphoid, distal tibia, base of the 5th metatarsal bone are at higher risk for non-union because of insufficient blood supply in these areas after fracture
    • Segmental fractures and those with loose fragments have an increased risk of non-union like because of compromise of the blood supply to the intercalary segment

Four types of bone non-union have been described 3:

1. Atrophic non-union:

  • Evidenced by radiographic absent callus, which indicates poor biology and a lack of blood supply
  • Might be a result of inadequate fixation

2. Hypertrophic non-union:

  • Shown by radiographic abundant callus formation
  • Importantly, there is no bridging bone, and the ends are not united
  • This finding implies there is adequate blood supply and biology (with the formation of callus), but inadequate stability

3. Oligotrophic non-union:

  • Is a balance and combination of atrophic and hypertrophic in that there is incomplete callus formation
  • Inadequate reduction

4. Septic non-union:

  • Reduces blood flow from organisms consuming the nutrition to healthy bone
  • Decreases the new bone formation

Treatment of non-unions is multidimensional and can consist of conservative treatment followed by operative treatment 4.

Conservative treatment:

  • Use of a fracture brace or immobilization in a cast postoperatively
  • Pulsed low-intensity ultrasound or other Ilizarov bone transport

Operative treatment:

Treatment is tailored on non-union type. Multiple surgical techniques exist and they need to be tailored to the patient’s specific needs.

Hypertrophic nonunion

Treatment goal is to improve mechanical stability with internal fixation

    • Compression plates
    • Exchange nailing
    • Augmented plating with ORIF
    • Dynamization with a nail

Atrophic nonunion

Treatment goal is to repair biology and mechanical stability

  • Internal fixation with biologic stimulation
      • Biologic stimulation with bone graft
      • Bone morphogenetic protein (BMP):
      • Autologous iliac crest bone graft
      • Intramedullary reaming, irrigation, and debris aspiration (RIA)
      • Demineralized bone matrix (DBM)
      • Systemic parathyroid hormone (PTH) therapy, teriparatide

Oligotrophic nonunion:

Can use a combination of both internal fixation and biologic stimulation depending on the clinical situation

Infected nonunion: Must obtain WBC, ESR, CRP, and nuclear bone scan. Intraoperative cultures are the gold standard for guided antibiotic therapy

  • A 2-staged surgical treatment protocol is the gold standard
      • 1st stage – removal of loose or chronic infected hardware, debridement, and revision fixation of nonunion, and treatment of infection with culture-specific local and systemic antibiotics
      • Modalities used for initial fixation in case of infection
          • Antibiotic beads
          • Antibiotic nails
          • Antibiotic cement spacers
          • Masquelet technique
          • External fixation
          • Soft tissue coverage with a flap
      • 2nd stage
        • Begins after a period of antibiotic therapy when both serologic and clinical signs of infection are absent
        • Definitive fixation proceeds with internal fixation and bone grafting, other biological treatment, bone transport, depending on specific fracture characteristics.


  1. Cunningham BP, Brazina S, Morshed S, Miclau T. Fracture healing: A review of clinical, imaging and laboratory diagnostic options. Injury. 2017 Jun;48 Suppl 1:S69-S75.
  2. Brinker MR, O’Connor DP, Monla YT, Earthman TP. Metabolic and endocrine abnormalities in patients with nonunions. J Orthop Trauma. 2007 Sep;21(8):557-70.
  3. Bell A, Templeman D, Weinlein JC. Nonunion of the Femur and Tibia: An Update. Orthop. Clin. North Am. 2016 Apr;47(2):365-75.
  4. Garnavos C. Treatment of aseptic non-union after intramedullary nailing without removal of the nail. Injury. 2017 Jun;48 Suppl 1:S76-S81.