External Ankle Support and Ankle Biomechanics in Chronic Ankle Instability: Systematic Review and Meta-Analysis.

Objective: To systematically review the literature to determine whether external ankle supports influence ankle biomechanics in participants with chronic ankle instability (CAI) during sport-related tasks.

Data Sources: A literature search of MEDLINE, SPORTDiscus, and CINAHL databases was conducted in November 2021.

Study Selection: Included studies were randomized crossover or parallel-group controlled trials in which researchers assessed ankle biomechanics during landing, running, or change of direction in participants with CAI using external ankle supports compared with no support.

Data Extraction: Two authors independently identified studies, extracted data, and assessed risk of bias (Cochrane risk-of-bias tool version 2) and quality of evidence (Grading of Recommendations Assessment, Development and Evaluation). Random-effects meta-analysis was used to compare between-groups mean differences with 95% CIs. Grading of Recommendations Assessment, Development and Evaluation recommendations were used to determine the certainty of findings.

Data Synthesis: A total of 13 studies of low to moderate risk of bias were included. During landing, very low-grade evidence indicated external ankle supports reduce frontal-plane excursion (mean difference [95% CI] = -1.83° [-2.97°, -0.69°], P = .002), plantar-flexion angle at initial contact (-3.86° [-6.18°, -1.54°], P = .001), and sagittal-plane excursion (-3.45° [-5.00°, -1.90°], P < .001) but not inversion angle at initial contact (-1.00° [-3.59°, 1.59°], P = .45). During running, very low- to low-grade evidence indicated external ankle supports reduce sagittal-plane excursion (-5.21° [-8.59°, -1.83°], P = .003) but not inversion angle at initial contact (0.32° [-2.11°, 1.47°], P = .73), frontal-plane excursion (-1.31° [-3.24°, 0.63°], P = .19), or plantar-flexion angle at initial contact (-0.12° [-3.54°, 3.29°], P = .94). Studies investigating changes of direction were insufficient.

Conclusions: Very low-grade evidence indicated external ankle supports reduce frontal-plane excursion but not inversion angle at initial contact in participants with CAI during landing. Limiting frontal-plane excursion may reduce ankle-sprain risk. Frontal-plane ankle kinematics were not influenced by external ankle supports during running. Sagittal-plane reductions were observed with external ankle supports during landing and running with low to very low certainty, but their influence on ankle-sprain risk is undetermined.