The ankle joint is a unique structure that depends on perfect alignment of the bones for normal function. Although the ankle moves in an up and down direction (called dorsiflexion and plantarflexion), there is very subtle movement with twisting, called rotation. In order for the ankle to work efficiently, the bones need to line up perfectly in the socket, which is called the mortise.
Ankle fractures range from relatively minor twisting injuries to those associated with violent disruption of the ankle. There are two different mechanisms of injury that have different effects on the structure of the ankle:
- A twisting mechanism and the body rotates around the foot
- A crushing type mechanism that impacts the foot
The twisting type of injuries are far more common, and although there is less likelihood of damage to the cartilage, the bones that make up the ankle joint must nonetheless be carefully re-aligned. The second type of injury that occurs from a fall from a height, or in a motor vehicle accident, is usually far more serious and often associated with cartilage damage.
The ankle consists of:
- Inner aspect of the tibia (the medial malleolus)
- Outer aspect of the ankle (the fibula)
- Bone underneath the ankle (the talus)
There are many different varieties and grades of severity of ankle fractures. These may involve only the medial malleolus, only the fibula, or both bones (which is called a bi-malleolar fracture). At times the talus may completely pop out of the ankle joint associated with the fracture, which is called a fracture dislocation.