Failed single-leg assessment of postural stability after anterior cruciate ligament injuries and reconstruction: An updated systematic review and meta-analysis

Background: Postural control deficits and persistent joint stability issues are prevalent in population with anterior cruciate ligament (ACL) injuries or reconstructions. Postural control is typically assessed using the center of pressure (CoP) parameters during the static single-leg stance with a force plate. However, previous studies have reported unclear definitions and descriptions of the CoP parameters, causing inconsistent results of postural control deficits in a specific population. Objective: To 1) summarize CoP parameters commonly used to evaluate postural control deficits in ACL injured or reconstructed population, and 2) identify the differences in CoP parameters with opened and closed eyes during the single-leg stance between ACL injured or reconstructed and control groups. Methods: PubMed, Embase, Cochrane Library, CINAHL, Scopus, Web of Science, and SPORTDiscus databases were searched up to July 2023. Data were obtained from the selected articles and underwent quality and risk of bias assessment and meta-analysis using random-effect models. Subgroup analysis within ACL injured or reconstructed group were also performed. Results: A total of 14 articles were included in the analysis after screening. The injured knee of the ACL injured or reconstructed group differed insignificantly in sway amplitude, sway area, and sway velocity during static singleleg stance under opened and closed eyes when compared with the control group. In the subgroup analysis, we found that there was only significant difference in sway velocity with open eyes (SMD = 0.47, p = 0.001) between ACL reconstructed group and control group. Conclusion: This study summarized the common CoP parameters used to evaluate postural control in ACL injured or reconstructed population. The results only showed weak difference in sway velocity between ACL reconstructed population and healthy individuals with opened eyes during the static single-leg stance.