Morphological characteristics of the lateral ankle ligament complex

Purpose The relevance of each ligament comprising the lateral ankle ligament complex, including the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL), has not been sufficiently elucidated; therefore, we aimed to clarify the morphological characteristics and relevance of these ligaments. Methods Total 152 legs from 152 Japanese cadavers were investigated. The lengths and widths of the ATFL, CFL, and PTFL were measured using a caliper. The ATFL was classified according to the number of fiber bundles (Types I, II, and III corresponded to one, two, and three fiber bundles, respectively), and the lengths and widths of the three ligaments were compared between the Type groups. In addition, the ratio of each ligament’s length and width to the tibial length was calculated, and the correlation of the ratio of ligament length and width between the ATFL, CFL, and PTFL was examined about 34 legs. Results The ATFL, CFL, and PTFL were found to connect at the anterior/inferior tip of the lateral malleolus each other. The Type II group of the ATFL was most common (54.6%) in our investigated specimens. However, there were no significant inter-group differences in the lengths and widths of the CFL and PTFL. Conclusions This study demonstrates that the lateral ankle ligaments may stabilize the ankle joint through interconnections.