[Posterior depression-separation fracture in bimalleolar fractures]

The authors analyse the anatomic character and the functional consequences of the posterior depression-separation in ankle fractures. The posterior depression fracture was present in 20 per cent of the ankle fractures of the studied series. The major depression was noticed 1 by 3. The lesion justified a specific operation. Its presence had also to be searched in rotation fractures treated conservatively, when the lateral malleolus was uncorrectly reduced. These two situations unnoticed or neglected create an incontinence of the talus leading to a triple desaxation, even if it does not appear on usual x-ray views. Tomographic sagittal x-ray views are on that score an important contribution to the diagnostic. Ankles showing such a residual defect deteriorated to an early articular narrowing during the first 6 months and to arthrosis during the first or second year.