Abstract

DUARTE SILVA, Miguel et al. Eixo de Mobilidade Tibio-Talar. Rev. Port. Ortop. Traum. [online]. 2019, vol.27, n.2, pp.91-102. ISSN 1646-2122.

There is still controversy about the variability of the talo crural axis during plantar and dorsiflexion of the ankle. Currrently, it is thought that there is a variable axis forthese two movements. A literature revision was conducted and we tested the application of the variable axis concept to the external fixation of the ankle, with the main goal of reducing the stiffness of the joint. Pubmed was searched using the key words “ankle axis” and “tibio-talar axis”, and the papers about ankle biomechanics were selected. Inman studies supports the idea of a single axis. Currently, the literature points more to the existence of a variable axis for the plantar and dorsiflexion movements. Studies such as that of Barnett and Napier or, more recently, of Lundberg, support this idea of a variable axis. Based on theories that advocate a variable axis and based on the Hicks concept that there cannot exist movements simultaneously in these two axis, an attempt was made to apply this concept in the placement of trans-articular external fixators in the ankle. By placing the calcaneus pin in the direction of the axis that favors dorsiflexion, the tendency for the foot to fall into equine position can be minimized, without the need for additional pins in the midfoot.

Keywords : Ankle biomechanics; tibio-talar axis; ankle external fixation.

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