Effects of Chronic Pain on Static and Dynamic Postural Control in Chronic Ankle Instability

Objective: To identify the effects of chronic pain levels on static and dynamic postural (DP) control in individuals with chronic ankle instability (CAI). Design: Cross-sectional study. Setting: Controlled laboratory. Participants: Sixty participants were divided into the following 3 groups: 20 high pain individuals with CAI (high pain), 20 low pain individuals with CAI (low pain), and 20 healthy controls (control). Independent Variables: Groups (CAI with high pain, CAI with low pain, and control) and visual conditions (eyes open and closed) for single-leg stance. Main Outcome Measures: Participants performed single-leg stance with eyes open and closed, the star excursion balance test, and single-leg hop to stabilization. Results: The high pain group experienced worse self-reported outcomes, including Foot and Ankle Ability Measure activities of daily living and sports, than the low pain and control groups. Regardless of visual condition, both the high and low pain groups exhibited decreased static postural control in mediolateral (ML) compared with the control group. Specifically, the high pain group showed decreased static postural control in ML under closed eyes compared with the low pain and the control groups. The high pain group showed less reach distance than the control group and increased DP control in vertical and overall DP stability index compared with the low and control groups. Conclusions: Chronic pain can significantly affect both static and DP control in individuals with CAI. Therefore, clinicians should consider chronic pain as one of the factors affecting postural control in individuals with CAI.