Fractures of the ankle involve ipsilateral ligamentous tears or bony avulsion and contralateral shear fractures. The pattern of fracture is determined by the mechanism of injury. Avulsion fractures are transverse and shear fractures are oblique (if pure inversion/eversion) or spiral (if rotational).
The X-ray above shows ankle joint of right lower limb. An avulsion (transverse) fracture can be appreciated on the lateral malleolus and a shear (oblique) fracture can be seen on the medial malleolus. This is a Danis-weber Type A (infra-syndesmotic) ankle fracture which occurs as a pure inversion injury (Supination-adduction according to Lauge Hansen classification). The avulsion of lateral malleolus is below the plafond. Open reduction and Internal fixation (ORIF) is recommended for Bimalleolar fractures.