Footprint of the lateral ligament complex of the ankle.

BACKGROUND: We describe the topographic anatomy of the lateral ligament complex of the ankle using 3-dimensional (3D) computed tomography (CT) imaging. METHODS: Dissection of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) was performed on 8 unpaired fresh-frozen cadaver feet. Ligaments were sharply dissected from bone, and the footprint was outlined with radio-opaque paint. The specimen underwent a 0.625-mm slice CT scan of the ankle with 3D reconstructions. Software was used to determine the surface area of the ligament footprint as well as measure the distance from the peroneal tubercle to the center of the CFL footprint. Data are presented as mean ± standard error. RESULTS: Six specimens had a bifid ATFL. Seven ankles had a bifid ATFL footprint on the talus. All specimens had intact CFL fibers. The intact superior and inferior limbs of the ATFL measured 19.7 ± 1.2 mm and 16.7 ± 1.1 mm. The CFL measured 24.8 ± 2.4 mm. The area of the footprints of the superior ATFL and inferior ATFL on the talus measured 1.5 ± 0.26 cm(2) and 0.90 ± 0.07 cm(2). The CFL and ATFL origins on the fibula were continuous and measured 3.48 ± 0.39 cm(2). The CFL insertion on the calcaneus measured 2.68 ± 0.20 cm(2). The CFL was found 27.1 ± 1.0 mm posterior and superior from the peroneal tubercle. CONCLUSIONS: In presumably uninjured specimens, both the ATFL and its footprint on the talus were bifid. The CFL and ATFL origins have a single confluent footprint on the anterior border of the distal fibula. The CFL footprint on the calcaneus is almost 3 cm posterior and superior to the peroneal tubercle. CLINICAL RELEVANCE: This study may assist surgeons in anatomically reconstructing the lateral ligament complex of the ankle.