Systematic review of postural control and lateral ankle instability, part I: can deficits be detected with instrumented testing

Abstract

Objective: To answer the following clinical questions: (1) Is poor postural control associated with increased risk of a lateral ankle sprain? (2) Is postural control adversely affected after acute lateral ankle sprain? (3) Is postural control adversely affected in those with chronic ankle instability?

Data sources: PubMed and CINAHL entries from 1966 through October 2006 were searched using the terms ankle sprain, ankle instability, balance, chronic ankle instability, functional ankle instability, postural control, and postural sway.

Study selection: Only studies assessing postural control measures in participants on a stable force plate performing the modified Romberg test were included. To be included, a study had to address at least 1 of the 3 clinical questions stated above and provide adequate results for calculation of effect sizes or odds ratios where applicable.

Data extraction: We calculated odds ratios with 95% confidence intervals for studies assessing postural control as a risk factor for lateral ankle sprains. Effect sizes were estimated with the Cohen d and associated 95% confidence intervals for comparisons of postural control performance between healthy and injured groups, or healthy and injured limbs, respectively.

Data synthesis: Poor postural control is most likely associated with an increased risk of sustaining an acute ankle sprain. Postural control is impaired after acute lateral ankle sprain, with deficits identified in both the injured and uninjured sides compared with controls. Although chronic ankle instability has been purported to be associated with altered postural control, these impairments have not been detected consistently with the use of traditional instrumented measures.

Conclusions: Instrumented postural control testing on stable force plates is better at identifying deficits that are associated with an increased risk of ankle sprain and that occur after acute ankle sprains than at detecting deficits related to chronic ankle instability.

Keywords: ankle sprains; balance; chronic ankle instability; stabilometry.

Figures

Figure 1. Flow chart for selecting articles to be included in the systematic review to answer our 3 questions. Article reference numbers are superscripted.

Figure 2. Was poor postural control associated with increased risk of ankle sprain? Odds ratios and 95% confidence intervals are shown for postural control as a risk factor for lateral ankle sprains. Individuals who sustained a first-time ankle sprain had worse postural control measures than those who did not go on to sustain sprains. ML indicates mediolateral; AP, anteroposterior. Article reference numbers are superscripted.

Figure 3. Was poor postural control associated with increased risk of ankle sprain? Effect sizes and 95% confidence intervals compare those who went on to sprain their ankles and those who did not. Findings are inconsistent as to whether those who sustained an ankle sprain had poorer postural control than those who did not. EO indicates eyes open; EC, eyes closed. Article reference numbers are superscripted.

Figure 4. Was postural control adversely affected by acute lateral ankle sprain? Effect sizes and 95% confidence intervals compare postural control measures for injured groups (acute lateral ankle sprain) with healthy groups. Postural control was adversely affected by acute lateral ankle sprain compared with healthy controls. ML indicates mediolateral; COP, center of pressure. Article reference numbers are superscripted.

Figure 5. Was postural control adversely affected by acute lateral ankle sprain? Effect sizes and 95% confidence limits compare postural control performance between injured and uninjured limbs in those with acute lateral ankle sprains. Whether actual deficits in postural control exist when comparing the injured with the uninjured side in those who suffered acute lateral ankle sprain is inconclusive. The results of Tropp et al are not shown here due to the large confidence intervals associated with the point measure of effect size (effect size for COP area  =  0.23, 95% confidence interval  =  −51.22, 51.48). ML indicates mediolateral; COP, center of pressure; AP, anteroposterior. Article reference numbers are superscripted.

Figure 6. Was postural control adversely affected by chronic ankle instability? Effect sizes and 95% confidence intervals compare healthy and chronic ankle instability groups. Whether postural control deficits existed in those with CAI compared with healthy controls is unclear. Effect sizes for Tropp (COP area  =  0.96, 95% confidence interval [CI]  =  −24.91, 26.83) and Cornwall and Murrell (anteroposterior COP length  =  .29, 95% CI  =  −17.60, 18.18; mediolateral COP length  =  .46, 95% CI  =  −17.43, 18.35) are not shown due to wide CIs. AP indicates anteroposterior; ML, mediolateral; EC, eyes closed; EO, eyes open; COP, center of pressure. Article reference numbers are superscripted.

Figure 7. Was postural control adversely affected by chronic ankle instability? Effect sizes and 95% confidence intervals compare affected and unaffected limbs in those with unilateral chronic ankle instability. Whether postural control deficits exist in the affected limb versus the unaffected limb in those with unilateral CAI is unclear. Results of Tropp are not displayed due to wide confidence intervals around the effect size (COP area  =  .26, 95% confidence interval  =  −32.54, 33.06). EC indicates eyes closed; EO, eyes open; AP, anteroposterior; ML, mediolateral. Article reference numbers are superscripted.