Gender differences in distance between the talus and lateral malleolus during gait using ultrasound in healthy adults

The anterior talofibular ligament connects the talus to the lateral malleolus and is an essential component in understanding the pathophysiology of ankle sprains. In recent years, ultrasound is often used in its evaluation, however, most of it remains a static assessment (Rein S et al., 2020). Are there gender differences in the dynamics of the distance between the talus and the lateral malleolus during the stance phase of gait using ultrasound in healthy adults? The participants in this study were 10 healthy males and 9 healthy females. All participants did not report a history of previous ankle sprains. We used a motion capture system (Vicon Motion Systems, UK) synchronized with an ultrasound (Art Us EXT-1H, Telemed, Vilnius, Lithuania) to examine the distance between the talus and the lateral malleolus during the stance phase of gait. The US probe (5-11 MHz, 60-mm field of view; Echoblaster, Telemed, Vilnius, Lithuania) was positioned on the lateral side of the ankle joint and visualized the most lateral part of the talus and lateral malleolus on the ultrasound screen. Participants walked at a comfortable speed on a force plate (OR-6, 1000 Hz: AMTI, USA) and the interval from heel contact to toe-off was included in the analysis. Tracker 5.1.5 software (Open-Source Physics) was used to calculate the distance between the talus and lateral malleolus and the amount of change with respect to that distance at heel contact. Unpaired t-tests were used to compare the gender differences in that distance in the early, middle, and terminal stance phases. The changes in the distance between the talus and the lateral malleolus were -0.15±1.15 mm in the early stance phase, -0.98±1.99 mm in the middle stance phase, and -0.77±1.99 mm in the terminal stance phase in males and -0.84±0.92 mm, -2.24±1.40 mm, and -0.64±1.52 mm in women, respectively. The changes in the distance were significantly higher in females than in males in the early and middle stance phases. In females, the distance between the talus and the lateral malleolus during the stance phase of gait is highly variable, and this hypermobility may be a risk for ankle sprains and future ankle osteoarthritis. Prior study has reported that joint laxity is greater in women than in men after puberty, which may affect the incidence of injury (Quatman CE et al., 2008). This study using ultrasound could provide a basic data for examining ankle dynamics during gait in patients with ankle sprains.