Trimalleolar Fracture-Dislocation of the Ankle with a Double Fragment of the Medial Malleolus: A Separate Fracture Subtype?

INTRODUCTION: Lauge-Hansen classification for ankle fractures is helpful in directing the management of the fracture and has got prognostic significance. However, trimalleolar fractures with double medial malleolar fracture are not yet described. CASE REPORT: Two cases of trimalleolar fracture-dislocation of the ankle with a double fracture of the medial malleolus are reported. Both of them had a Weber B fracture of the lateral malleolus, accompanied by a posterior dislocation of the ankle and a fracture of the posterior malleolus. The medial malleolus though presented an interesting variation, a large vertical or oblique fragment was combined with a small horizontal fragment of its tip. CONCLUSION: We propose a separate subtype in the Lauge-Hansen classification of supination with combined external rotation and adduction when this pattern of the medial malleolus is accounted. Awareness of this fracture pattern will help better pre-operative planning.