Postural Control Deficits During Static Single-leg Stance in Chronic Ankle Instability: A Systematic Review and Meta-Analysis

Context: Postural control deficits arising from injured ankles are central to chronic ankle instability (CAI) and its persistent symptoms. This is usually measured by recording the center of pressure (CoP) trajectory during static single-leg stance using a stable force plate. However, existing studies have produced conflicting results on whether this mode of measurement adequately reveals the postural deficits in CAI. Objective: To determine whether postural control during static single-leg stance is impaired in CAI patients when compared with uninjured healthy controls. Data Sources: Literature databases, PubMed, Embase, Web of Science, Cochrane Library, Scopus, CINAHL, and SPORTDiscus, were searched from inception to April 1, 2022, using ankle-, injury-, and posture-related terms. Study Selection: Two authors independently performed the step-by-step screening of article titles, abstracts, and full texts to select peer-reviewed studies investigating CoP trajectory during static single-leg stance using a stable force plate in CAI patients and healthy controls. A total of 13,637 studies were reviewed, and 38 studies (0.003%) met the selection criteria. Study Design: Meta-analyses of descriptive epidemiological study. Level of Evidence: Level 4. Data Extraction: CoP parameters, sway directions, visual condition, and numerical data (means and standard deviations) were extracted. Results: The injured ankles of CAI patients had higher standard deviations of sway amplitude in both anterior-posterior and medial-lateral directions (standardized mean difference [SMD] = 0.36 and 0.31, respectively) under conditions of open eyes than controls. Higher mean sway velocity in anterior-posterior, medial-lateral, and total directions (SMD = 0.41, 0.37, and 0.45, respectively) with closed eyes was also found. Conclusion: CAI patients had deficits of postural control during static single-leg stance, and these deficits were identified by the CoP trajectory. Further methodological explorations of CoP parameters and corresponding test conditions are required to enhance the sensitivity and reliability of postural deficit assessments in CAI using force plates.