"Double Maisonneuve fracture": an unknown fracture pattern.

Objective: The aim of this study was to describe pathoanatomy and to raise awareness of a fracture of the lateral malleolus combined with a high subcapital fracture of the fibula caused by a dislocation mechanism.

Methods: The study comprised 11 patients, 5 men and 6 women, with the mean age of 57 years (range, 21-87), with a "Double Maisonneuve fracture". Individual lesions of ankle structures were described on the basis of radiographs, CT, and intraoperative findings.

Results: The distal fibular fracture was classified as Weber type B in 1 case and Weber type C in 10 cases. The proximal fibular fracture was described as a subcapital oblique spiral fracture with metadiaphyseal involvement in nine cases and a high short oblique fracture with fibular head involvement in two cases. Injury to the deltoid ligament was revealed in six cases; a bicollicular fracture of the medial malleolus was found in five patients. Posterior malleolar fractures were classified as type 1 in eight cases and type 2 in three cases. Avulsion of the Chaput tubercle was detected in four cases. Injury to the interosseous tibiofibular ligament was assessed in nine patients.

Conclusions: Double Maisonneuve fracture is a rare but probably underreported injury that must be taken into consideration during examination, as it may be easily overlooked. The essential part of diagnosis is a careful clinical examination and radiological assessment of the lower leg with additional CT examination of the ankle.