The Relationship Between Fibular Notch Anatomy and ATFL Rupture

The anterior talofibular ligament (ATFL) is the first to be damaged during a lateral ankle sprain. Dynamic and static structures have been investigated to better understand ATFL rupture, but the predisposing factors have not been fully elucidated. This study aims to define the fibular notch version that can evaluate the position of the fibular notch relative to the tibia and investigate the relationship between the fibular notch version (FNV) and ATFL rupture. This study included 71 patients with isolated ATFL rupture diagnosed clinically and radiologically and 71 control patients without any foot or ankle pathologies. Anterior facet length (AFL), posterior facet length (PFL), anterior-posterior facet angle (APFA), fibular notch depth (ND), and FNV measurements were performed on axial magnetic resonance images (MRI). We defined FNV as a parameter that evaluates the fibular notch's relative position to the distal tibia. The mean FNV was 16.6^° ± 4.9^° in patients with ATFL rupture and 12.4^° ± 5.6^° in the control group; when both groups were compared, FNV measurements were significantly higher in patients with ATFL rupture (p = .002). The mean APFA was 123.9^° ± 10^° in the group with ATFL rupture and 129.7^° ± 7.8^° in the control group. When both groups were compared, APFA was significantly lower in patients with ATFL rupture (p = .014). There was no significant difference between the groups regarding AFL, PFL, and ND. A more posterior (retroverted) fibular notch and a lower fibular notch angle seem to be associated with higher rates of ATFL rupture.