Diagnosis

44-A2 Infrasyndesmotic lateral lesion, with fracture of the medial malleolus

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Type A2 fractures occur with the foot supinated and an adduction force applied to the talus. The first injury occurs below the syndesmotic ligament on the lateral side, which is under tension. Secondly, the talus tilts which causes a shearing compression fracture of the medial malleolus. 44-A2 fractures correspond to the supination-adduction fractures stage II in the Lauge-Hansen classification.

Options
1. 44-A2.1 Rupture of the lateral collateral ligaments
2. 44-A2.2 Avulsion of the tip of the lateral malleolus
3. 44-A2.3 Transverse fracture of the lateral malleolus

1. 44-A2.1 Rupture of the lateral collateral ligaments

44-A2.1

44-A2.1

Lateral malleolus
Rupture of the lateral collateral ligaments (the calcaneo-fibular ligament and the anterior and posterior talo-fibular ligaments).

Medial malleolus
Oblique or vertical fracture.

44-A2.1 AP view

44-A2.1 AP view

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

2. 44-A2.2 Avulsion of the tip of the lateral malleolus

44-A2.2

44-A2.2

Lateral malleolus
Avulsion of the tip.

Medial malleolus
Oblique or vertical fracture.

In type A2 fractures, the superomedial corner of the talus may act as a blunt chisel and 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 (see x-ray for 44-A2.3 fractures). The impacted “corner” fragment will need to be reduced, prior to reduction and fixation of the medial malleolus.

44-A2.2 AP view

44-A2.2 AP view

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

3. 44-A2.3 Transverse fracture of the lateral malleolus

44-A2.3

44-A2.3

44-A2.3 with impacted

44-A2.3 with impacted "corner" fragment

Lateral malleolus
Infrasyndesmotic transverse fracture.

Medial malleolus
Oblique or vertical fracture.

In type A2 fractures, the superomedial corner of the talus may act as a blunt chisel and 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.

44-A2.3

44-A2.3