Radiographic Anatomy of the Lateral Ankle Ligament Complex: A Cadaveric Study

Abstract

Category: Ankle; Sports Introduction/Purpose: Lateral ankle sprains are common orthopedic injuries that may progress on as chronic lateral ankle instability (CLAI). Great care must be taken to restore precise anatomic relationships of the lateral ankle ligament complex (LALC) in the surgical management of CLAI. This study aimed to quantify the radiographic relationships between the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and prominent osseous landmarks visible under fluoroscopy to assist in perioperative practices for minimally invasive surgery (MIS) for CLAI. Methods: Ten fresh frozen ankle specimens were dissected to expose the LALC and prepared by threading a radiopaque filament through the ligamentous footprints of the ATFL and CFL. Lateral ankle fluoroscopic images were obtained and digitally analyzed to define dimensional characteristics of the ATFL and CFL. Directional measurements of the ligamentous footprints relative to the lateral process of the talus and the apex of the posterior facet of the calcaneus were also calculated. Results: Dimensional measurements of the ATFL included a mean length of 9.3 mm, fibular footprint of 9.4 mm, and talar footprint of 9.1 mm. Dimensional measurements of the CFL included a mean length of 19.4 mm, fibular footprint of 8.2 mm, and calcaneal footprint of 7.3 mm. From the lateral process of the talus, the fibular attachment of the ATFL was found 13.3 mm superior and 4.4 mm posterior, while the talar attachment was found 11.5 mm superior and 4.8 mm anterior. From the apex of the posterior facet of the calcaneus, the fibular attachment of the CFL was found 0.2 mm inferior and 6.8 mm anterior, while the calcaneal attachment was found 14.3 mm inferior and 5.9 mm posterior. Conclusion: The ATFL and CFL were radiographically analyzed in a unique manner and localized in reference to two prominent osseous landmarks. These findings may assist in perioperative practices for keyhole incision placement and arthroscopic guidance.