Ankle fracture, Weber C

The fibula breaks above the syndesmosis. The force has torn the tibiofibular ligaments and usually the deltoid ligament, so the distal fibula and talus drift laterally: the mortise is unstable by definition.

Mechanism

Pronation–external rotation (Lauge-Hansen PER). The extreme form is the Maisonneuve injury: fracture of the proximal fibula with a complete syndesmotic tear.

Clinical findings

• Medial tenderness and swelling; palpate the whole fibula up to the knee (Maisonneuve).

Imaging

• AP, mortise and lateral of the ankle.
• Full-length tibia and fibula: a proximal fibular fracture (Maisonneuve) means the syndesmosis is torn.
• CT for posterior malleolus and syndesmosis when in doubt.

• Ankle series plus full-length tibia and fibula. Widened tibiofibular clear space (> 6 mm) and medial clear space.
• CT (bilateral) is useful to judge syndesmotic reduction.

Classification

44C1

Simple diaphyseal fibula fracture.

44C2

Multifragmentary fibula.

44C3

Proximal fibula (Maisonneuve).

Types shown in 3D

44C1

Simple diaphyseal fibula fracture above the syndesmosis; syndesmosis and deltoid torn, the talus drifts laterally.

44C2

Multifragmentary fibula above the syndesmosis.

44C3

Proximal fibula (Maisonneuve): the whole interosseous membrane is torn up to the fracture. Fix the syndesmosis; the fibula itself usually not.

Treatment

Operative (standard)

Restore fibular length and rotation (plate), then reduce the syndesmosis under direct vision with the ankle in neutral and fix it with one or two 3.5 mm screws or a suture-button device. Repair or fix the medial side if it blocks reduction.

Maisonneuve

The fibula itself usually does not need fixation: reduce and fix the syndesmosis.

Aftercare

Non- or partial weight bearing for about 6 weeks; syndesmotic screws are sometimes removed after 8–12 weeks.

Complications

• Syndesmotic malreduction (the main cause of poor results)
• Screw breakage
• Post-traumatic arthritis