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

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.

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

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.

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.

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.

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.