Ankle Injuries During Excessive External Foot Rotation May Depend on Foot Constraint: Development of a Computational Model

摘要

Numerous studies on the mechanisms of ankle injury deal with injuries to the syndesmosis and anterior ligamentous structures, but previous sectioning and clinical studies also describe the important role of the posterior talofibular ligament (PTaFL) in the ankle's resistance to external rotation of the foot. Foot constraint may influence subtalar motion and the movement of the bones in the foot, thereby influencing the mode of injury during external rotation [1]. Stiehl et al. [2] constrain the foot with fiberglass cast tape, externally rotate the foot 90°, and produce injury to the deltoid ligament and anterior tibiofibular ligament (ATiFL) with bone fracture. In contrast, Stormont et al. [3] fix the foot in a potting alloy and conclude the primary ligamentous restraints to external rotation are the PTaFL and calcaneofibular ligament (CaFL).A recent study in our laboratories, using two different manners of foot fixation (potted and taped), document failure characteristics of the human cadaver ankle under controlled external rotation of the foot [I]. The PTaFL related injuries are noted in 5 of 9 ankles with a potted foot, and damage to the anterior deltoid ligament is noted in 3 of 4 ankles with a taped foot [1].