Continuous and Connective Fibers of the Lateral Ankle Ligament Complex.

The lateral ankle ligament complex (LALC) is an intricate structure; therefore precise anatomic knowledge is required by the surgeon. However, the structural relationship of the LALC remains unclear. Here, the features of the posterior talofibular ligament (PTFL) and the relationship to the LALC at the distal fibula were clarified in a cadaver study. The lengths of most of the anterior and posterior parts, and the widths of the anterior-posterior and superior-inferior parts, were measured with a digital caliper. In addition, the relationship between the anterior talofibular ligament (ATFL) and PTFL inside of the capsule is described. The small fiber bundles of the PTFL were manually divided, and the footprint of each bundle at the fibula and talus was clarified. The relationship between the ATFL and CFL, outside of the capsule, was examined on axial slices at the inferior fibula. The lengths of the most anterior and most posterior parts of the PTFL were 9.8 ± 1.7 and 29.4 ± 1.9 mm, respectively. The widths of the anterior-posterior and superior-inferior parts were 10.0 ± 0.9 and 5.8 ± 1.1 mm, respectively. Approximately 83% of the fibers between the ATFL and PTFL were continuous. The anterior-inferior fibers of the PTFL were continuous with the inferior fibers of the ATFL inside of the capsule. The ATFL and CFL converged with connective tissue from outside of the capsule at the distal fibula. The results of this study should prove useful to further clarify the relationships of the LALC both inside and outside of the capsule at the distal fibula.