Diagnosis

Infrasyndesmotic lateral lesion, with posteromedial fracture (AO/OTA 44A3) 

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In some cases, the medial fracture may cause a circumferential lesion, with a posterior extension. These are classified as AO/OTA 44A3 fractures.

There is no special fracture type in the Lauge-Hansen classification of supination-adduction fractures that describes this posterior marginal extension of the medial lesion.

Complete radiological evaluation (AP, lateral and AP with internal rotation) is crucial for correct classification and decision making.

Options
1. Rupture of the lateral collateral ligaments (AO/OTA 44A3.1) 
2. Avulsion of the tip of the lateral malleolus (AO/OTA 44A3.2) 
3. Transverse fracture of the lateral malleolus (AO/OTA 44A3.3) 

1. Rupture of the lateral collateral ligaments (AO/OTA 44A3.1) 

Rupture of the lateral collateral ligaments (AO/OTA 44A3.1)

Rupture of the lateral collateral ligaments (AO/OTA 44A3.1)

If the lateral malleolus is intact, and the lateral injury involves a rupture of the lateral collateral ligaments (the calcaneo-fibular ligament and the anterior and posterior talo-fibular ligaments), with a posteromedial malleolar fracture, this is classified as an AO/OTA 44A3.1 fracture.

Radiograph taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.

2. Avulsion of the tip of the lateral malleolus (AO/OTA 44A3.2) 

Avulsion of the tip of the lateral malleolus (AO/OTA 44A3.2)

Avulsion of the tip of the lateral malleolus (AO/OTA 44A3.2)

If the lateral injury involves a transverse fracture of the lateral malleolus, with a posteromedial malleolar fracture, this is classified as an AO/OTA 44A3.2 fracture.

In these fractures, the superomedial corner of the talus may cause, not only a high oblique or vertical medial malleolar fracture, but also an impaction fracture of the “medial corner” of the tibia, at the junction of its horizontal joint surface (plafond) and the medial malleolar joint surface. This is effectively a “split depression” injury, analogous to that of the tibial plateau. The impacted “corner” fragment will need to be reduced, prior to reduction and fixation of the medial malleolus.

3. Transverse fracture of the lateral malleolus (AO/OTA 44A3.3) 

Transverse fracture of the lateral malleolus (AO/OTA 44A3.3)

Transverse fracture of the lateral malleolus (AO/OTA 44A3.3)

If the lateral injury involves a transverse fracture of the lateral malleolus, with a posteromedial malleolar fracture, this is classified as an AO/OTA 44A3.3 fracture.

In these fractures, the superomedial corner of the talus may cause, not only a high oblique or vertical medial malleolar fracture, but also an impaction fracture of the “medial corner” of the tibia, at the junction of its horizontal joint surface (plafond) and the medial malleolar joint surface. This is effectively a “split depression” injury, analogous to that of the tibial plateau. The impacted “corner” fragment will need to be reduced, prior to reduction and fixation of the medial malleolus.

Radiograph taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.