Considerable disagreement exists concerning the mechanism by which the
relatively uncommon oblique fracture of the medial malleolus is produced,
and to our knowledge the relationship between it and a fracture of the
anterolateral aspect of the tibial plafond has not previously been
recognized. We treated a patient with these fractures whose deformed
steel-reinforced work boot indicated that the mechanism of injury had been
external rotation, dorsiflexion, and abduction. We found this fracture
pattern in eleven other patients. We concluded that the malleolar fracture
is an oblique avulsion injury and that impingement of the talus on the
anterolateral aspect of the tibial plafond accounts for the other fracture.
The identification of an oblique medial malleolar fracture should prompt a
search for a fracture of the anterolateral aspect of the tibial plafond;
the reverse is also true.