Also known as a fracture of the posterior tibial lip.
Mechanism of Injury:
This injury is usually associated with a rupture of the anterior tibiofibular ligament. Therefore, if a widening of the medial clear space and/or syndesmosis is detected (such as in a high ankle sprain), it is important that one examine the posterior malleolus. Similarly, if anterior or posterior capsule distension is seen, and /or Kager's fat pad is obliterated, consider the posterior malleolus.
Important: Large fragments (i.e. greater than 25% of the tibial plafond) require surgical intervention (open reduction + internal fixation).