The effect of genu varum deformity on balance control following postural perturbation in adolescent girls

Despite the fact that balances has often been considered as a measure of lower extremity function، the effect of lower extremity malalignment on balance performance has received little attention. The aim of the present study was to examine postural control following a sudden external perturbation in adolescent girls with genu varum of the knees in comparison to age matched healthy controls. This comparative and interventional study included eight adolescent girls with genu varum (age: 13. 5± 1. 4 years) and eight age-matched healthy controls (age: 13. 8 ± 1. 3). The subjects underwent unexpected forward، backward and medio-lateral perturbations triggered by a weight equivalent to 10% of the body weight، of every subject while standing on a foot pressure system mounted on a movable plate. The displacement of the center of pressure (COP) of the feet was measured. Independent t-test was used for statistical analysis. p≤0. 05 was considered significant. Subjects with genu varum of the knees showed a significantly greater COP displacement after perturbation in comparison to the control group (p=0. 039). Our findings revealed that postural control following balance perturbations is weaker in subjects with genu varum deformity than in control group. Consequently، abnormal lower limb alignment is a risk factor which can influence postural control in response to a balance perturbation.