Diagnosis

44-C1 Suprasyndesmotic diaphyseal fibular fracture, with medial lesion

print

Type C fractures occur with the foot in pronation when an external rotation force is applied. The first injury is a failure of the medial side, either with a deltoid ligament rupture, or a medial malleolar fracture. This frees the talus to move anteriorly as it rotates externally. The talus causes the fibula to rotate externally around its longitudinal axis, sequentially tearing the anterior and interosseous ligaments. Finally the fibula fractures proximal to the syndesmosis.

44-C fractures correspond to pronation-eversion fractures, stages I-IV, in the Lauge-Hansen classification. This is an especially unstable joint lesion that may demand - depending on its stage – a syndesmotic positioning screw.

Options
1. 44-C1.1 Simple, with ruptured medial collateral ligament
2. 44-C1.2 Simple, with fracture of the medial malleolus
3. 44-C1.3 With fractured medial malleolus and a Volkmann

1. 44-C1.1 Simple, with ruptured medial collateral ligament

44-C1.1

44-C1.1

Fibula
A simple, oblique, or transverse, diaphyseal fracture occurs above the syndesmotic ligaments; displaced.

Medial lesion
Rupture of the medial collateral ligament.

Syndesmotic complex
This is always disrupted. In some cases, the posterior tibio-fibular ligament may be intact.

44-C1.1 AP and lateral view

44-C1.1 AP and lateral view

2. 44-C1.2 Simple, with fracture of the medial malleolus

44-C1.2

44-C1.2

Fibula
A simple, oblique, or transverse, diaphyseal fracture occurs above the syndesmotic ligaments; displaced.

Medial lesion
A transverse, or oblique, fracture of the medial malleolus.

Syndesmotic complex
This is always disrupted. In some cases, the posterior tibio-fibular ligament is intact.

44-C1.2 AP and lateral view

44-C1.2 AP and lateral view

3. 44-C1.3 With fractured medial malleolus and a Volkmann

44-C1.3

44-C1.3

Fibula
A simple, oblique, or transverse, diaphyseal fracture occurs above the syndesmotic ligaments; displaced.

Medial lesion
A transverse, or oblique, fracture of the medial malleolus.

Posterior tuberosity of the tibia
The fracture of the posterior tibial lip may be a small cortical avulsion. Rarely in 44-C fractures does a larger fragment, bearing a variable area of the posterior articular surface, fracture off.

Syndesmotic complex
While the foot rotates externally, the anterior and interosseous syndesmotic ligaments rupture. In the 44-C1.3 lesions, the posterior tibio-fibular ligament may avulse its posterior tibial attachment.  The talus, very rarely, is forced backwards and compresses the posterior lip of the distal tibial joint surface until a Volkmann lesion results.

It is possible that some of these injuries represent vertical compression (posterior pilon) fractures, such as the x-rays below.

44-C1.3 AP and lateral view

44-C1.3 AP and lateral view