Ankle Fracture/dislocation

Basics

Common mechanisms and injury patterns of the ankle:

Mechanism of injury:
- Inversion injury: Lateral ankle distraction and medial ankle compression
  - Avulsion fracture of the lateral malleolus
  - Oblique fracture of the medial malleolus
- Eversion injury: Medial ankle distraction and lateral ankle compression
  - Avulsion fracture of medial malleolus
  - Oblique fracture of the fibula
- External rotation injury:
  - Disruption of the tibiofibular syndesmosis, or a fibular fracture above the plafond
  - Anterior or posterior tibial fracture with separation of the distal tibia and fibula (unstable fracture)
- Inversion and external rotation (Maisonneuve fracture):
  - Medial malleolus avulsion fracture or deltoid ligament tear
  - Disruption of the tibiofibular syndesmosis
  - Oblique fracture of the proximal fibula
- Inversion and dorsiflexion (snowboarders’ fracture):
  - Fracture of the lateral process of the talus
- Posterior dislocation is most common. Results from backward force on plantar flexed foot. Often with rupture of tibiofibular ligaments or lateral malleolus fracture
Epidemiology:
- Most ankle fractures are malleolar
- Common in young male and 50–70 yr old female
- Associated with cigarette use and high BMI

Pediatric Considerations

Ankle fractures in children often involve the physis (growth plate):
- May result in angular deformity from growth plate injury
- Associated with sports requiring sudden changes in direction and obese children
- In children <10 yr old, growth plate is weaker than epiphysis
Tillaux fracture: Salter–Harris type III injury of the anterolateral tibial epiphysis external rotation of the foot
Triplane fracture: Uncommon fracture of distal tibia with fracture lines in 3 distinct planes (coronal, transverse, sagittal)

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