The effect of stroboscopic visual disruption on static stability measures in anterior cruciate ligament reconstructed individuals

Background: Those who undergo ACL reconstruction are at an increased risk of suffering a second ACL injury. A suggested rationale for the increased injury risk is sensory reweighting to the visual system to compensate for a lack of somatosensory information from the knee. Understanding this proposed visual reliance may help clinicians improve return to sport outcomes and reduce the risk of a subsequent ACL injury. Methods: Thirteen ACL reconstructed individuals and thirteen matched controls completed two common static postural control assessments under three different visual conditions; eyes open, low visual disruption, and high visual disruption. Center of pressure data was collected for 30 s using force plates. Static postural stability was evaluated using the following: 1) root mean square distance, 2) mean velocity, 3) sway area, and 4) mean frequency. Findings: No significant interactions between group and vision were observed. Significant differences between groups were observed for mean frequency in the double-limb stance (p < .05). Additionally, significant differences were observed for visual conditions in both double-limb (mean velocity; p < .05) and single-limb stances (root mean square distance, mean velocity, sway area, and mean frequency; p < .05). Interpretation: The findings of the current study suggest that ACL reconstructed individuals, who are at least two years removed from surgery, do not rely on visual information to a greater extent than controls during static postural stability assessments. Stroboscopic glasses may be a cost-effective alternative for rehabilitation purposes compared to the traditional binary eyes open vs. eyes closed methods.