Description

• Fractures involve the distal fibula (lateral malleolus) and/or distal tibia (medial malleolus and plafond). Lateral malleolus fractures are the most common type of ankle fracture.
• Common fractures with ligamentous injury:
  • Maisonneuve fracture: Proximal fibular fracture with distal ligametous rupture and avulsion of medial malleolus
  • Osteochondral fracture of the talar dome
  • Avulsion fracture of the 5th metatarsal
• 2 common classification systems are useful for describing fractures; however, Lauge Hansen has recently been shown to be superior for detecting syndesmotic injury after comparison with MRI as a gold standard (1)[B]:
  • Danis-Weber system: Type A, B, C based on the location of the fibular fracture in relationship to the syndesmosis:
    • Type A: Below the level of syndesmosis (of tibiofibular joint)
    • Type B: At the level of the syndesmosis; both usually stable
    • Type C: Above syndesmosis; usually unstable; Lauge Hansen: Fracture type based on foot position and applied force, with the most basic nomenclature referring to the number of fractures:
      • Unimalleolar:
        • Lateral malleolus if type C, unstable
        • Medial malleolus fracture usually occurs in conjunction with ligamentous or lateral/posterior malleolus injury.
      • Bimalleolar: Both the medial and lateral malleolus; usually unstable
      • Trimalleolar: Lateral, medial, and posterior malleoli; unstable
• Pilon fracture: Intra-articular fracture of the tibial plafond; usually axial loading mechanism; unstable

• The distal tibial and fibular physis is the 3rd most common fracture in children.

• Distal tibia is most common site of pathologic fracture.
• Injuries are more likely to affect the growth plate.
• Juvenile Tillaux: Isolated Salter-Harris (SH) III fracture of anterolateral portion of the distal tibia epiphysis
• Triplane fracture: SH IV; occurs in adolesence; 2-, 3-, and 4-part fractures:
  • Most commonly epiphyseal fragment anteriorly and metaphyseal fragment posteriorly

Epidemiology

• Predominant ages: Even age distribution
• Predominant sex:
  • Age <50: Male > Female
  • Age >50: Female > Male
• Unimalleolar (fibular fractures) = 60–70%; bimalleolar = 15–20%; trimalleolar = 7–12%

• 1–2 cases per 1,000 people per year
• Rising incidence and severity in the elderly; seen in as many as 8.3 Medicare patients per 1,000 (2)[B]

Risk Factors

• Increased body mass index
• History of smoking or osteoporosis

General Prevention

• Proper shoe wear (i.e., flat, supportive shoes)
• Fall precautions in the elderly
• Avoid, or use caution for, activities on uneven or slick surfaces, or when fatigued.

Pathophysiology

• The location and pattern of injury depend on foot position and the direction of force applied.
• Most commonly, the foot is plantar flexed and inverted, and the force is external rotation.
• Axial loading can cause a tibial plafond or pilon fracture.

Etiology

• Fall or twisting injury to the ankle
• Alcohol or slippery surfaces (1/3 of injuries, each)
• Sports: The ankle is the most commonly injured joint among athletes.

Commonly Associated Conditions

• Ligamentous injury (sprains):
  • Lateral collateral sprains are the most common (85–90%); medial collateral sprains and distal syndesmotic are uncommon.
• Syndesmosis injury
• Ankle or subtalar dislocation
• Fractures of metatarsals, talus, or calcaneus
• Osteochondral fractures
• Posterior ankle impingement (os trigonum)
• Peroneal tendon dislocation
• Compartment syndrome (rare)
• Neurovascular injury (rare)
• Other axial loading or shearing injuries (i.e., vertebral compression fractures or contralateral pelvic fractures)