The more proximal fibular fractures indicate a risk of syndesmotic disruption and ankle instability.
Type A is an internal rotation and adduction injury. The fracture of the fibular is below the level of the tibial plafond. It is usually an avulsion injury from supination of the foot. It may be associated with an oblique or vertical medial malleolus fractures. Syndesmotic disruption is rare, but it can occur.
Type B is an oblique or spiral fractures of the fibula near or at the level of syndesmosis. This is an external rotation injury. It may be an associated injury to the medial structures of the posterior malleolus. Occurrence of a syndesmotic injury is 50%.
Type C is an abduction injury. The fracture of the fibula is above the level of syndesmosis. Syndesmosis disruption always occurs. In almost all cases there is an associated medial injury. It includes a maisonneuve fracture pronation abduction or pronation external rotation.