Bilateral balance impairments after lateral ankle trauma: a systematic review and meta-analysis

Research indicates that balance is impaired in the involved limb following an ankle injury. However, bilateral balance impairments are a viable reason for previous non-significant findings between involved and uninvolved limbs. The purpose of this investigation was to conduct a meta-analysis on studies reporting the effects of lateral ankle trauma on balance of the involved and uninvolved limb after acute ankle injury and chronic ankle instability. Twelve studies qualified for inclusion and assessed static balance for both the involved and uninvolved limbs post-injury and a control group. Meta-analyses calculated standardized mean difference effects and explored moderating variables for the involved and uninvolved limbs relative to controls. A significant cumulative effect size (ES=0.448, p<0.00001) indicated that balance of the involved limb is impaired after a history of ankle injury. Moderator variable analysis revealed that both acute (ES=0.529, p<0.0002) and chronic (ES=0.338, p<0.001) lateral ankle trauma negatively affected balance. Analysis of the uninvolved limb also revealed postural stability impairments (ES=0.275, p<0.003). Additional, moderator analysis showed a significant acute effect (ES=0.564, p<0.0001), but failed to find significance for individuals with chronic ankle instability (ES=0.070, p=0.552). These findings provide strong evidence that balance is bilaterally impaired after an acute lateral ankle sprain. However, these findings suggest that bilateral balance deficits are not present in patients with chronic ankle instability. Based on these findings, the uninvolved limb should not be used as a reference for "normal balance" following an acute lateral ankle sprain. Further, patients with acute lateral ankle sprains should undergo balance training on both limbs.