Ankle Fractures

Basics

  • Bones: tibia, fibula, talus
  • Mortise joint: tibial plafond, fibula above (forming medial and lateral malleolus) and talus below
  • Ligaments: syndesmotic, lateral collateral, and medial collateral (deltoid) ligaments

Description

  • Two common classification systems help describe most fractures (but do not always predict fracture stability).
    • Danis-Weber: based on level of the fibular fracture in relationship to the tibiotalar joint
      • Type A (30%): below ankle joint; usually stable
      • Type B (63%): at the level of the ankle joint; may be stable or unstable
      • Type C (7%): above ankle joint; usually unstable
    • Lauge-Hansen (LH): based on foot position and direction of applied force relative to the tibia
      • Supination-adduction (SA)
      • Supination-external rotation (SER): most common (40–75% of fractures)
      • Pronation-abduction (PA)
      • Pronation-external rotation (PER)
  • Stability-based classification
    • Stable
      • Isolated lateral malleolar fractures (Weber A/B) without talar shift and with negative stress test
      • Isolated nondisplaced medial malleolar fractures
    • Unstable
      • Bi- or trimalleolar fractures
      • High fibular fractures (Weber C) or lateral malleolar fracture with medial injury and positive stress test
      • Lateral malleolar fracture with talar shift/tilt (bimalleolar equivalent)
      • Displaced medial malleolar fractures
  • Pilon fracture: tibial plafond fracture due to axial loading (unstable)
  • Maisonneuve fracture: fracture of proximal 1/3 of fibula associated with ankle fracture or ligament disruption (unstable); high risk of peroneal nerve injury

Pediatric Considerations

  • Ankle fractures are more common than sprains in children compared to adults because ligaments are stronger than physis.
  • Talar dome fracture: osteochondral fracture of talar dome; suspect in child with nonhealing ankle “sprain” or recurrent effusions
  • Tillaux fracture: isolated Salter-Harris III of distal tibia with growth plate involvement
  • Triplane fracture: Salter-Harris IV with fracture lines oriented in multiple planes: 2-, 3-, and 4-part variants

Epidemiology

  • Ankle fractures are responsible for 9% of all adult and 5% of all pediatric fractures.
  • Peak incidence: females 45 to 64 years; males 8 to 15 years (average is 46 years)

Incidence
107 to 184 per 100,000 people per year

Etiology and Pathophysiology

  • Most common: falls (38%), inversion injury (32%), sports related (10%)
  • Plantar flexion (joint less stable in this position)
  • Axial loading: tibial plafond or pilon fracture

Risk Factors

  • Age, fall, fracture history, polypharmacy, intoxication
  • Obesity, sedentary lifestyle
  • Sports, physical activity
  • History of smoking or diabetes
  • Alcohol or slippery surfaces

General Prevention

  • Nonslip, flat, protective shoes
  • Fall precautions in elderly

Commonly Associated Conditions

  • Most ankle fractures are isolated injuries, but 5% have associated fractures, usually in ipsilateral lower limb.
  • Ligamentous or cartilage injury (sprains)
  • Tibiotalar or subtalar dislocation
  • Other axial loading or shearing injuries (i.e., vertebral compression or pelvic fractures)

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