When the lateral injury is a transverse fracture of the lateral malleolus below the syndesmotic ligament this classified as an AO/OTA 44A1.3 fracture.
Infrasyndesmotic fractures (AO/OTA Type 44A) occur with the foot supinated and an adduction force applied to the talus, causing the lateral structures to fail in tension. Isolated lateral side injuries, with the medial side intact, are classified as AO/OTA group 44A1. These correspond to supination-adduction fractures stage I in the Lauge-Hansen classification.
Complete radiological evaluation (AP, lateral and AP with internal rotation) is crucial for correct classification and decision making.