Outer ankle fracture

Fibular fracture, malleolar fracture, bimalleolar fracture, trimalleolar fracture, Weber fractures, fracture of the fibula, fracture of the external ankle,


Ankle fractures such as the outer ankle fracture are fractures of the ankle joint fork with varying degrees of pronounced fracture. Both the inner and the outer ankle can be affected. With 10% of fractures, they are the third most common fracture in humans.

In more than 80% of cases, the external ankle fracture is the result of a traumatic dislocation (subluxation/dislocation) of the ankle bone from the joint forming ankle fork, mostly caused by a false step or fall (ankle injury). A direct violent impact as a cause is rare. Depending on the foot position at the moment of injury and the magnitude of the force applied, different injury patterns occur (see classifications).


The outer ankle fracture is the most common injury to the upper ankle joint. The symptoms caused by the external ankle fracture (fracture) are basically dependent on the type of injury and the structures involved in the ankle. On the one hand, it is important to distinguish at what height the fracture is located.

In doing so, the physician orientates himself or herself on the ligament that ultimately holds the two ankles together. On the other hand, any fracture of the outer ankle may also involve ligaments or, more rarely, bones on the inner ankle, which may be overstretched or torn. Typical symptoms are a swelling with redness or bruising on the affected foot, pain when stepping on the foot or touching the ankle. There may be a restriction of movement or a complete inability to put any weight on the foot at all with a possible unstable feeling. In some cases, a fracture of the outer ankle can lead to malpositioning of the joint or sensory disturbances on the affected area.

Explanation of terms

  • Malleolar fracture = outer or inner ankle fracture
  • Bimalleolar fracture = outer and inner ankle fracture
  • Trimalleolar fracture = outer and inner ankle fracture plus fracture of the posterior edge of the tibia (posterior Volkmann triangle)


The most common classification of ankle fractures / fibula fractures in everyday clinical practice is that according to Danis and Weber (Weber 1966). It refers exclusively to the fracture height of the fibula in relation to the syndesmosis: If not only the outer ankle is affected by the fracture, a distinction is made in everyday clinical practice between

  • Bimalleolar fracture
  • Trimalleolar fracture
  • Comminuted fractures: Destruction of the bony ankle joint with involvement of the inner and outer ankle and the tibial pilon (tibial tibia). – Weber A: Fracture of the tip of the outer ankle below the syndsmosis.

Syndesmosis always intact. – Weber B: Fracture of the outer malleolus at the level of the syndesmosis. Syndesmosis mostly injured, but not necessarily with resulting instability of the ankle fork.

  • Weber C: Fracture of the lateral malleolus above the syndesmosis. Syndesmosis always torn with resulting instability of the ankle fork. With the AO classification all fracture forms of the ankle joint can be classified exactly: A-fracture: ankle fracture below the syndesmosis B-fracture: ankle fracture at the level of the syndesmosis C-fracture: ankle fracture above the syndesmosis The classification according to Lauge-Hansen (1950) distinguishes 4 types of dislocation fractures, taking into account the position of the foot at the time of the accident, as well as the direction and extent of the applied force:
  • A1 Simple external ankle fracture
  • A2 External and internal ankle fracture
  • A3 External and internal ankle fracture with postero-medial fracture
  • B1 Simple external ankle fracture
  • B2 External and internal ankle fracture
  • B3 External and internal ankle fracture with postero-lateral fracture (Volkmann’s triangle)
  • C1 Simple diaphyseal fibular fracture
  • C2 Diaphyseal fibula fracture, multi-fragmented
  • C3 Proximal fibula fracture
  • Supination-adduction fracture (bending over the outer edge of the foot)
  • Pronation abduction fracture (bending over the inner edge of the foot = less frequent)
  • Supination-eversion fracture (2/3 of all fractures) = injury mechanism as in the case of a torn ligament
  • Pronation Eversion Fracture