In fracture-dislocation of the ankle, one should make sure that the upper fragment of the fibula is not caught behind the posterolateral ridge of the tibia. In some instances, fracture of the lateral malleolus does not occur until the foot has twisted beneath the ankle joint, drawing the fibula behind the tibia and breaking it off against the posterior margin thereof. When this occurs, the fibula is firmly caught and needs open reduction with a pry; severe disability is likely to occur unless accurate replacement is made by operative means.