General principles of fractures

A fracture is a partial or complete interruption in the continuity of bone. The most common causes are trauma and diseases (e.g., osteoporosis) that result in weakened bone structure. The latter results in pathologic fractures, which are fractures that would not usually occur if the bone structure was not weakened. Open fractures, in which the bone is exposed due to severe soft tissue injury, are associated with a significant risk of infection and poor wound healing. Fracture management can be conservative (e.g., cast or splint) or surgical, and generally involves anatomic reduction, fixation, and/or immobilization. Complications include acute nerve and vascular injury and compartment syndrome, as well as long-term complications such as avascular necrosis and nonunion.

• Trauma: mechanical stress and/or loading
• Weakened bone structure: osteoporosis, bone tumors, metastasis, Paget disease

References:^[1]

Fracture classification is based on the following:

• Anatomy
  • Location: affected bone (proximal, distal)
  • Position: diaphysis, metaphysis, epiphysis
• Extent
  • Complete
  • Incomplete
• Orientation: transverse, oblique, spiral
• Displacement: nondisplaced, displaced, angulated
  • Rotated = rotation around the longitudinal axis
  • Angulated = angulation of the axis
  • Translated = lateral movement of the bone fragments
  • Longitudinal displacement of bone fragments
    • Distraction = elongation
    • Impaction = shortening
• Fragmentation
  • Comminuted fracture
  • Segmental fracture
• Soft tissue involvement
  • Closed fracture (simple fracture)
  • Open fracture
• Growth plate involvement (pediatric fractures): Salter-Harris fractures

AO classification system

The AO Foundation (Association for the Study of Internal Fixation) classifies long bone fractures according toanatomical location, position, and complexity of the fracture. It provides a numerical coding system for the anatomical location and position of the fracture, and an additional letter to denote the complexity of the fracture.

Anatomical location

• 1 = Humerus
  • Clavicle
  • Scapula
• 2 = Radius/ulna
• 3 = Femur
  • Patella
• 4 = Tibia/fibula
• 5 = Spine
• 6 = Pelvis
• 7 = Hand
• 8 = Foot
• 9 = Skull

Position

• 1 = Proximal
• 2 = Diaphyseal
• 3 = Distal

Complexity

• A = Simple or extra articular
• B = Wedged or partial articular
• C = Complex or complete articular

References:^[2][3]

Common fractures in children

See “Pediatric fractures” for details.

Common fractures in adults

• Pathologic fracture
• Open fracture
  • A fracture in which bone fragments break through the skin
  • Secondary to trauma
  • Associated with significant soft tissue injury and an increased risk of complications (infection, poor healing)
• Stress fracture
• Forearm fractures
  • Colle's fracture: distal radius ± distal ulna
  • Smith fracture: distal radius
  • Monteggia's fracture: proximal one-third of the ulna and dislocation of the radial head
  • Galeazzi's fracture: distal radial shaft and dislocation of the distal radioulnar joint
• Boxer's fracture: fifth metacarpal neck
• Scaphoid fracture
• Ankle fracture
• Tibial fracture
• Femoral shaft fracture
• Femoral neck fracture
• Pelvic fracture
• Vertebral fractures (including compression fractures)

References:^[2][4][5]

• Pain, redness, and swelling at the site of injury
• Deformity and axis deviation
• Bone fragments penetrating the skin
• Palpable step-off or gap
• Bone crepitus
• Concomitant soft tissue injuries
• Neurovascular compromise below site of injury

• Clinical assessment
  • Assess for signs of a fracture and concomitant injuries
  • Assess for neurovascular compromise and compartment syndrome with the 6 P's: pain, pallor, pulselessness, paresthesia, paralysis and poikilothermia
• Imaging
  • X-ray
    • Conditions:
      • 2 views
      • 2 joints (if limb fracture)
      • 2 times (prereduction and postreduction)
    • Radiographic signs of a fracture include a radiolucent fracture line and cortical disruption
    • Describe fracture based on the anatomic location, alignment , angulation, and articular involvement (see “Classification” above for details)
    • X-ray imaging has a low sensitivity for detecting stress fractures
  • CT/MRI (not routine)
    • Indications: preoperative planning for complicated fractures, assessment of associated injuries, and inconclusive x-ray findings.

References:^[6][7]

• Acute complications
  • Neurologic and vascular injury (eg. bleeding, hematoma, seroma)
  • Compartment syndrome
  • Wound infection, osteomyelitis
  • Secondary dislocation
• Long-term complications
  • Avascular necrosis
  • Complex regional pain syndrome
  • Post-traumatic osteoarthritis
  • Joint stiffness/contracture
  • Joint instability
  • Heterotopic ossification
  • Children: growth disturbances after growth plate injury (→ Salter-Harris fracture)
  • Refracture
  • Nonunion: incomplete healing of a fracture
    • Risk factors: poor vascular supply, insufficient immobilization, open fractures, infection, smoking, comorbidities (diabetes mellitus, osteoporosis)
    • Clinical features: pain, swelling, limited weight-bearing capacity, and reduced range of motion persisting after the normal duration of healing (usually 6–9 months)
    • Forms
      • Hypertrophic nonunion: callus formation in the fracture zone
      • Atrophic nonunion: atrophic bone without callus formation
      • Pseudarthrosis of inflammatory origin
    • Treatment: debridement and resection, osteosynthesis (fixation), antibiotics in the case of infected nonunion
• Complications due to immobilization
  • Thrombosis, pulmonary embolism
  • Infections (e.g., pneumonia, urinary tract infection)

References:^[3][8]

We list the most important complications. The selection is not exhaustive.