Article

Lateral ankle anesthesia has been used as a model to explore effects of ligament
deafferentation related to ankle sprain on single limb postural control with conflicting results. Time-to-boundary (TTB) is a postural control measurement
technique found to be sensitive in detecting subtle deficits in postural control
in those with chronic ankle instability.
The objective of this study was to
determine the effects of lateral ankle ligament anesthesia on TTB measures of
single limb postural control in healthy adults. Twenty-two healthy adults with no
history of lower extremity injury within the past 6 months or balance disorders
participated in the study. All subjects received a lidocaine injection to the
lateral ankle structures on one of two testing days. On both testing days,
subjects performed 3 eyes open and 3 eyes closed, 10-s trials of barefoot single
limb stance on a forceplate. The dependent variables were the mean of TTB
minima(s) and standard deviation of TTB minima(s) in mediolateral (ML) and anteroposterior (AP) directions. Separate condition (anesthesia, control) by
vision (eyes open, eyes closed) ANOVAs with repeated measures were used for each
TTB variable to determine the effects of anesthesia on postural control. Alpha
level was set a priori at p</=0.05. The anesthesia day TTBAP magnitude (p=0.008)
and variability (p=0.044) measures were significantly lower than the control day,
regardless of vision. Anesthesia of the lateral ankle ligamentous structures
significantly reduced the magnitude and variability of TTBAP measures. These
findings are similar to deficits found in those with chronic ankle instability.
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Langue : ANGLAIS