Effects of soft and semi-rigid ankle orthoses on postural sway in people with and without functional ankle instability

Some studies have demonstrated improvement of postural control following use of ankle supports, whereas others reported no effect or even negative effects of bracing. The present study aimed to investigate the immediate effects of soft and semi-rigid orthosis on postural sway in patients with functional ankle instability (FAI). Twenty patients with unilateral FAI and twenty matched healthy individuals participated in the study. Balance in single limb stance on force platform with eyes-open was assessed for both legs while wearing no orthosis (control condition), soft or semi-rigid orthosis. The center of pressure (COP) measures derived from force platform signals were mean total velocity, standard deviation (SD) of velocity and phase plane portrait. A 2 × 2 × 3 (group by foot by orthotics) mixed model analysis of variance was used for statistical analysis. In the FAI group, there was a tendency to lower COP parameters while wearing either of the orthoses, with soft brace having a greater effect. For 2 dependent variables, significant effect of brace was found only for the injured limb. In the healthy group, postural sway increased from no-brace condition, to soft, to semi-rigid orthosis. Both injured and non-injured limbs of patients with FAI had greater postural sway compared to control limbs of healthy individuals.