Bilateral Sensorimotor Impairments in Individuals with Unilateral Chronic Ankle Instability: A Systematic Review and Meta-Analysis

Abstract

Background: Chronic ankle instability (CAI) is manifested by sensorimotor impairments in the sprained ankle, including deficits in sensation, motor function, and central integration or processing. These impairments have a significant impact on physical activities and daily life. Recently, some studies have suggested that bilateral deficits were observed in unilateral CAI, but contradictory evidence disputes this finding. Therefore, the objective of this study was to investigate whether bilateral sensorimotor deficits presented in individuals with unilateral CAI.

Methods: Without language restriction, the following databases were retrieved from database inception up until 3 November 2023, including PubMed, WOS, EMBASE, Cochrane, SPORTDiscus and CINAHL. Case-control and cross-sectional studies that investigated bilateral sensorimotor functions in individuals with unilateral CAI were included. Sensorimotor functions contained static and dynamic balance, functional performance, muscle strength and activation, as well as sensation. Outcome measures contained centre-of-pressure parameters, normalised reach distance, activation time and magnitude of muscle, sensory errors and threshold. The risk of bias and quality assessment of included studies were evaluated using a standardised tool recommended by the Cochrane Collaboration and the Epidemiological Appraisal Instrument, respectively. To explore the potential bilateral deficits associated with unilateral CAI, a comprehensive meta-analysis was conducted using Review Manager version 5.4. The analysis compared the injured limb of unilateral CAI with healthy controls and the uninjured limb with healthy controls. The main focus of this study was to investigate the differences between the uninjured limb and healthy controls. A random-effects model was employed and effect sizes were estimated using the standardised mean difference (SMD) with 95% confidence intervals (CIs). Effect sizes were deemed as weak (0.2-0.5), moderate (0.5-0.8), or large (> 0.8).

Results: A total of 11,442 studies were found; 30 studies were contained in the systematic review and 20 studies were included in the meta-analysis. Compared with healthy controls, those with unilateral CAI presented weak to moderate impairments in their uninjured limbs in static balance with eyes open (SMD = 0.32, 95% CI: 0.08 to 0.56), functional performance (SMD = 0.37; 95% CI: 0.08 to 0.67), kinesthesia (SMD = 0.52; 95% CI: 0.09 to 0.95) and tibialis anterior activation (SMD = 0.60, 95% CI: 0.19 to 1.01). There were no significant differences in other comparisons between the uninjured limb and healthy controls.

Conclusions: Patients with unilateral CAI may present bilateral deficits in static balance with eyes open, functional performance and kinaesthesia. However, further evidence is required to confirm this point due to limited studies included in some analyses and small effect size.

Registration: The protocol was registered in the International Prospective Register of Systematic Reviews platform (CRD: 42,022,375,855).

Keywords: Balance; Bilateral deficits; Injured; Kinaesthesia; Neuromuscular control; Proprioception; Sensorimotor; Uninjured.

Fig. 1

Flow chart of the study selection process

Fig. 2

Forest plot of static balance with eyes open (a) and eyes closed (b) comparing CAI with control. Hertel and Olmest-Kramer, 2007a (velocity of centre pressure in mediolateral direction) and b (velocity of centre pressure in anteroposterior direction) [30]; Mitchell et al., 2008a (velocity of centre pressure in mediolateral direction) and b (velocity of centre pressure in anteroposterior direction) [33]. CAI chronic ankle instability, CI confidence interval, CON control, SMD standardized mean difference. Positive SMD indicates balance deficits in CAI

Fig. 3

SMD values and 95% CI for dynamic balance tests. AP anteroposterior, APSI anteroposterior stability index, AP-TTB anteroposterior time to boundary, CAI chronic ankle instability, CI confidence interval, CON control, COP centre of pressure, ML mediolateral, MLSI mediolateral stability index, ML-TTB mediolateral time to boundary, SD standard deviation, SI stability index, SMD standardised mean difference. In the study by Simpson et al. [15], negative SMD indicates balance deficits in CAI. In other three studies [31, 37, 50], positive SMD indicates balance deficits in CAI

Fig. 4

Forest plot of functional performance comparing CAI with control. Sharma et al., 2011a (single-limb hopping), b (Single-limb hurdle) and c (single hop) [7]. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Positive SMD indicates functional performance deficits in CAI

Fig. 5

Forest plot of muscle strength comparing CAI with control. Porter et al., 2022a (120°/s concentric) and b (240°/s concentric) [45]. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Negative SMD indicates strength deficits in CAI

Fig. 6

SMD values and 95% CI for isometric and maximal muscle contraction. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Negative SMD indicates strength deficits in CAI

Fig. 7

Forest plot of muscle activation magnitude comparing CAI with control. Kim et al., 2012a (prone), b(bipedal) and c(unipedal) [52]; Song and Wang, 2018a (before landing) and b (inversion perturbation after landing) [53]. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Negative SMD indicates activation deficits in CAI

Fig. 8

Forest plot of muscle activation time comparing CAI with control. Sousa et al., 2018a(support) and b(perturbation) [47]. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Positive SMD indicates delayed activation in CAI

Fig. 9

Forest plot of sensation at the ankle comparing CAI with control. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Positive SMD indicates sensory deficits in CAI

Fig. 10

Sensitivity analysis for dorsiflexion. CAI chronic ankle instability, CON control, CI confidence interval, SMD standardised mean difference. Negative SMD indicates dorsiflexor strength deficit in CAI