MECHANICS OF THE ANTERIOR DRAWER AND TALAR TILT TESTS - A CADAVERIC STUDY OF LATERAL LIGAMENT INJURIES OF THE ANKLE

We analyzed the changes in lateral ligament forces during anterior dra wer and ta[ar tilt testing and examined ankle joint motion during test ing, following an isolated lesion of the anterior talofibular ligament (ATFL) or a combined lesion of the ATFL and calcaneofibular ligament (CFL). 8 cadaver specimens were held in a specially designed testing a pparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. Ligament forces were measured with buckle transducers, and joint motion was me asured with an instrumented spatial linkage. An anterior drawer test w as performed using an 80 N anterior translating force, and a talar til t test was performed using a 5.7 Nm supination torque with intact liga ments, after sectioning of the ATFL, and again after sectioning of the CFL. The tests were repeated at 10 degrees dorsiflexion, neutral, and 10 degrees and 20 degrees plantarflexion. In the intact ankle, the la rgest increases in ATFL force were observed during testing in plantarf lexion, whereas the largest increases in CFL force were observed in do rsiflexion. Isolated ATFL injury caused only small laxity changes, but a pronounced increase in laxity was observed after a combined CFL and ATFL injury.