Description

• Two common classification systems help describe fractures (but do not always predict fracture stability).
  • Danis-Weber system: based on level of the fibular fracture in relationship to the ankle 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 of proximal 1/3 of fibula associated with ankle fracture (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: osteochondral fracture of talar dome; suspect in child with nonhealing ankle “sprain” or recurrent effusions
• Tillaux: 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)
• Ankle or subtalar dislocation
• Other axial loading or shearing injuries (i.e., vertebral compression or contralateral pelvic fractures)