Abstract
Fracture of the lateral process of the talus (FLPT) is one of the common, yet frequently missed, fractures in snow boarders and can cause severe long-term disability if not treated properly. This fracture has been thought to result from dorsiflexion and inversion combined with axial loading. This assumption is based on injury mechanism reported by patients and anatomical studies and has not been supported by experimental data. We have to understand the mechanism of fracture generation in order to identify potential preventive strategies in equipment design or snowboarding techniques.
In order to understand the pathomechanics of FLPT generation we conducted dynamic impact tests on 19 fresh cadaver lower limbs. A test apparatus was constructed to deliver a pure inversion or eversion moment to the foot and ankle along the centre of rotation of the subtalar joint. An axial load of 2.5 kN was applied to all the legs. The legs were tested in four configurations: inversion with and without dorsiflexion, and eversion with and without dorsiflexion. All the specimens underwent post-test radiographic examination and a necropsy.
Necropsy revealed various injuries including ligamental injuries, malleolar fractures, osteochondral fractures of the talus and joint subluxations. In this study, ten cadaveric leg specimens were subjected to inversion or eversion of an axially loaded and dorsiflexion ankle. Inversion failed to produce any LPT fractures in three injured specimens. However, all six specimens subjected to eversion sustained an LPT fracture. Eversion of an axially loaded and dorsiflexion ankle may be an important injury mechanism for LPT fracture in snowboarders.
The abstracts were prepared by Mr Richard Buxton. Correspondence should be addressed to him at Bankton Cottage, 21 Bankton Park, Kingskettle, Cupar, Fife KY15 7PY, United Kingdom
