Lateral talocalcaneal instability following section of the calcaneofibular ligament: a kinesiologic study.

In the evaluation of the role of the calcaneofibular ligament in stabilizing the talocalcaneal joint, an experimental set-up was prepared. In 10 osteoligamentous specimens, the talocalcaneal motion was measured under a constant well defined moment by using a specially constructed apparatus. By using a moment of 1.5 Nm, increment in adduction in the talocalcaneal joint after section of the calcaneofibular ligament was found between 3.1 degrees and 4.6 degrees, still increasing with dorsiflexion. This increment, shown to constitute 61 to 77% of the total increment in adduction in the hindfoot after section of the calcaneofibular ligament, was found to increase gradually with dorsiflexion. The study has shown the calcaneofibular ligament as an important structure in stabilizing the talocalcaneal joint. Increment in adduction in the hindfoot after section of the calcaneofibular ligament was shown primarily to take place in the talocalcaneal joint.