[Supination external rotation lesions of the ankle joint in osteoporotic lower leg specimens. Experimental induction and review of the literature].

BACKGROUND: Knowledge of the pathomechanism and the detailed extent of ankle joint lesions determines adequate therapy and success of treatment.
MATERIAL AND METHODS: Supination external rotation lesions were induced in 29 human cadavera with a testing apparatus; 27 of these specimens were from elderly women. Bone mineral density was measured. The literature review includes experimental studies of this fracture entity.
RESULTS: We induced stage II in 42%; applying an additional lateral force on the fibula raised the incidence. The syndesmosis stayed intact in 50% although the fibula fractured at the level of the tibial plafond. Stage IV lesions were registered in 25%. The overall low bone mineral density showed a positive correlation to the angle at which the fibula fracture occurred.
CONCLUSIONS: We reproduced supination external rotation lesions according to Lauge-Hansen in osteoporotic ankles. There is a certain discrepancy between the obligatory lesion of the inferior anterior tibiofibular syndesmosis at stage II according to Lauge-Hansen, as we observed an intact syndesmosis in 50% at stage II. Stage IV defining medial malleolar fractures were reproduced after Lauge-Hansen and Michelson et al.