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.

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.

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.

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 single-leg 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.

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.

Ankle-foot sprains are the most common musculoskeletal injuries, which can impair balance and theoretically increase the risk of falls, but still, there is a lack of evidence supporting the direct association between ankle-foot sprains and the future risk of falls.

UK Biobank cohort was utilized to measure the association between ankle-foot sprains and fall risk with covariates adjusted. Then, the two-sample Mendelian randomization (MR) analysis was applied based on the genetically predicated ankle-foot sprains from FinnGen to validate causal relationship. Finally, genetically predicated cerebellar neuroimaging features were used to explore the mediating role of maladaptive neuroplasticity between ankle-foot sprains and falls by two-step MR analyses.

Patients with ankle-foot sprains history exhibited a slightly increased risk of falls than the matched controls before and after adjustment for covariates (odd ratio [OR] ranged from 1.632 to 1.658). Two-sample MR analysis showed that ankle-foot sprains led to a higher risk of falls (OR ​= ​1.036) and a lower fractional anisotropy of superior cerebellar peduncle (SCP) (left, β ​= ​−0.052; right, β ​= ​−0.053). A trend of mediating effect was observed for the fractional anisotropy of right SCP in the causal effects of ankle-foot sprains on falls (β ​= ​0.003).

The history of ankle-foot sprains is associated with a slightly increased risk of falls. These findings improve our understanding of the clinical consequences of ankle-foot sprains in terms of fall risk and suggest the importance of adopting more efficient strategies for managing residual functional deficits after the injuries.