Lateral ankle sprain alters postural control in bipedal stance--part 1: restoration over the 30 days following the injury.

The time evolution of the postural behavior of 23 lateral ankle sprain patients (degrees I and II) were evaluated 14 h and 10 and 30 days on average after their injury and compared with those of 30 age-matched healthy individuals. The patients were tested with separate measurements of the reaction forces under each limb to highlight the possible compensatory mechanisms between the sound and the injured legs. Their postural behavior in bipedal stance was characterised by a weight-bearing asymmetry with more weight on the sound leg and an asymmetry of the postural stabilisation mechanisms, which are limited and perturbed under the injured leg. Pain appears to be the main factor for explaining these postural asymmetries. Despite these asymmetries, the patients were nonetheless more unstable than the individuals constituting the group control. Ten days later, only the weight-bearing asymmetry was still observed whereas 30 days later, the postural behavior was totally normal once again. Lateral ankle sprain perturbs the contribution of the injured leg in postural stabilisation, inducing a larger involvement of the sound leg in the postural stability process. These characteristics are largely reduced 10 days after the injury.