Classification of ankle fractures: an algorithm.

In 1950, Lauge-Hansen devised a classification of ankle fractures based on the position of the foot and the deforming force at the time of injury. This has been widely accepted by orthopedists, but is not in general use by radiologists. An algorithm based on his classification that allows rapid assessment of the mechanism of injury in 90%-95% of cases has been devised by the authors. Identification of the fractures and classification of the type of injury allows diagnosis of the otherwise occult ligamentous injuries. On the basis of location and appearance of the fibular fracture, the four types of injuries are immediately identified: pronation-abduction, pronation-lateral rotation, supination-adduction, and supination-lateral rotation. Subsequent assessment for medial malleolar fracture and then posterior malleolar fracture defines the stage of completeness of the injury and localizes the sites of ligamentous disruption.