Objective
To investigate the deficit of static and dynamic postural control in patients with chronic ankle sprain using dynamic posturography.

Method
Twenty patients with unilateral recurrent ankle sprain and functional instability were assessed by Samsung medical center ankle injury score and by computerized dynamic posturography (EquiTest^Ⱂ system, Neurocom^Ⱂ, international, INC; USA).

The posturography test was performed 3 times at 6 different simulated conditions such as fixed of force platform/open eyes/fixed of screen (condition 1), fixed/closed/fixed (condition 2), fixed/open/movement (condition 3), sway/open/fixed (condition 4), sway/closed/fixed (condition 5), sway/open/movement (condition 6). We evaluated anteroposterior sway of center of gravity of the patients and calculated equilibrium scores. We compared the equilibrium scores of patient group and normal data reported previously. We also compared the equilibrium scores of two subgroups of the patients according to severity of ankle injury.

Results
Patients showed significantly low equilibrium scores than normal one at the condition 4, 5 and 6 (p＜0.05). The group B with severe ankle injury revealed low equilibrium scores at the condition 4, 5 and 6. Especially the group B showed statistically significance at condition 5 (p＜0.05).

Conclusion
Patients with chronic ankle sprain showed the deficit of dynamic postural control due to the proprioceptive dysfunction of injured ankle than normal person.