Does the contralateral healthy ankle of patient with ipsilateral mechanical lateral ankle laxity show greater lateral ankle laxity? Evaluation of the anterior talofibular ligament by stress ultrasonography.

BACKGROUND

A number of studies have evaluated risk factors for lateral ankle sprain (LAS) or chronic lateral ankle instability (CLAI). However, the definitive risk factors for LAS or CLAI remain controversial. The purpose of this study was to evaluate whether the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity (group I) show greater lateral ankle laxity in comparison to the healthy ankles of bilateral healthy controls (group B).

METHODS

From March 2020, anterior talofibular ligament (ATFL) lengths of young adult volunteers were cross-sectionally measured in non-stress and stress positions using a previously reported stress ultrasonography (US) procedure. The ATFL ratio (the ratio of stress ATFL/non-stress ATFL length) was calculated as an indicator of lateral ankle laxity. The manual anterior drawer test (ADT) was also performed. The US findings of healthy ankles from groups I and B were compared.

RESULTS

A total of 154 subjects in group B (mean age, 24.5 ± 2.8 years; male/female, 84/70) and 40 subjects in group I (mean age, 24.4 ± 2.3 years; male/female, 26/14) were included in the study. There was no significant difference in the ADT between the groups. There were no significant differences in the non-stress ATFL length (19.4 ± 1.8 vs. 19.3 ± 1.9, p = 0.84), stress ATFL length (20.8 ± 1.8 vs. 20.9 ± 1.9, p = 0.66), length change (1.5 ± 0.6 vs. 1.6 ± 0.6, p = 0.12) and ATFL ratio (1.08 ± 0.03 vs. 1.08 ± 0.03, p = 0.13) between the groups.

CONCLUSION

No significant difference was detected between the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity and those of bilateral healthy controls.