2012 Annual Conference

Croy, Theodore

US Army-Baylor University Doctoral Program in Physical Therapy, Fort Sam Houston, TX

Lateral ankle sprains and ligament injuries may result in anterior talar shift and lead to restrictions in dorsiflexion and posterior talar glide. Ultrasound imaging can visualize sagittal plane talar position and show changes in talar position between subjects with and without a history of ankle sprain. The purpose of this study was to determine if the talus shifts anteriorly in subjects with and without a history of chronic ankle instability (CAI).

Three subject groups (control (n=17), ankle sprain copers (n=20), and chronic ankle instability (CAI, n=20)

Participants underwent ultrasound imaging of the anterolateral ankle gutter to identify the lateral malleolus and talus over 3 trials. Between trials, subjects actively plantar and dorsiflexed the ankle 3 times. The sagittal plane talar position was found by measuring the anteroposterior distance (mm) between the lateral malleolus and talus.

Between group and trial differences were analyzed with repeated measures ANOVA and post hoc t-tests. Cohen's d effect sizes were also used to characterize changes between trials and differences between groups.

57 subjects participated. A significant group-by-trial interaction was observed (F_4,108=2.5, p=.049). Sagittal plane talar position shifted anteriorly in both copers (2.4 ± 3.6mm 95% CI: .73, 4.1, p=.007) and CAI (4.1 ±4.6mm 95% CI: 1.9, 6.2, p=.001) at Trial 3 while no changes were observed in control ankle talar position (.06 ± 2.8 95% CI: -1.5, 1.4, p=.93). The effect size difference for the CAI vs control comparison at trial 3 was large (Cohen's d=0.85, 95% CI: 0.18, 1.54) suggesting a clinically meaningful difference in anterior talar position occurred.

A history of ankle sprain may be accompanied by transient and measurable changes in anteroposterior talar position that can be visualized with ultrasound imaging. These findings may have implications for talocrural joint mobilizations following ankle sprains.

Restrictions in ankle motion following ankle sprain may be associated with changes in talar position which may be affected by manual therapy procedures such as anteroposterior talar mobilizations.