Biomechanics of Ankle Ligament Reconstruction

Abstract

We wanted to use biomechanical testing in a cadaveric model to compare the Broström repair, the Watson- Jones reconstruction, and a new anatomic reconstruc tion method. Eight specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantar flexion and supination-pronation) could be varied in a controlled manner. Testing was done with intact ligaments and was repeated after sectioning of the anterior talofibular ligament and the calcaneofibular ligament and after a Broström repair, a Watson-Jones reconstruction, and a new anatomic re construction were performed. An anterior drawer test was performed using an anterior translating force of 10 to 50 N, and a talar tilt test was performed using a supination torque of 1.1 to 3.4 N-m. The forces in the anterior talofibular ligament and calcaneofibular liga ment were measured with buckle transducers, and tibiotalar motion and total ankle joint motion were meas ured with an instrumented spatial linkage. The in crease in ankle joint laxity observed after sectioning of both the anterior talofibular and calcaneofibular liga ments was significantly reduced by the three recon structive techniques, although not always to the level of the intact ankle. Joint motion was restricted after the Watson-Jones procedure compared with that in the intact ankle. Unlike the Watson-Jones procedure, the ligament or graft force patterns observed during load ing after the Broström repair and the new anatomic technique resembled those observed in the intact ankle.