X-ray features to predict ankle fracture mechanism.

INTRODUCTION

The genetic Lauge-Hansen classification has been traditionally used for reconstruction of the mechanism of ankle injury. The ability of the Lauge-Hansen classification to predict actual mechanism of the injury has been questioned in recent studies, leaving a void in medicolegal reasoning. The aim of this study is to identify morphologic features of malleolar fractures on plain X-rays that may be used to reveal the fracture mechanism.

MATERIAL AND METHODS

Radiographs of 78 patients with acute malleolar fractures were analyzed and compared with fracture mechanisms reported by these patients.

RESULTS

A modified Pankovich classification of medial malleolus fractures and the presence of a posterior malleolus fracture were able to significantly predict the mechanism of fracture reported by the patient (p<0.05). Lateral fracture morphology was not useful for predicting the fracture mechanism except for infrasyndesmotic fractures pointing to a supination mechanism.

CONCLUSION

A supination mechanism of the fracture can be predicted by observing pure ligamentous or chip-avulsion deltoid injury. The presence of an anterior colliculus fracture of the medial malleolus is correlated with a pronation mechanism. A fracture of the posterior malleolus correlates with pronation while an intact posterior malleolus correlateds with supination as a fracture mechanism. Absolute determination of fracture mechanism from the X-ray morphology of the fracture is impossible in the majority of cases.