The influence of varus forefoot on plantar pressure distribution and on lower limb biomechanics

Abstract

Compensated forefoot varus might be associated to injuries in the foot and in more proximal joints. It is believed that this deformity can cause excessive medial rotation of the tibia and femur during the stance phase of gait, therefore altering the mechanics of the knee and hip joints. However, the influence of compensated varus forefoot in the kinematics of the hip and knee joints has not been effectively assessed. Moreover, this forefoot deformity could also produce alterations in the plantar pressure distribution and cause foot injuries due to areas of excessive pressure. Finally, if the compensated varus forefoot deformity actually results in alterations on hip kinematics, it could be assumed that adaptations in the muscles of this joint could occur. Therefore, the purpose of this study is to assess the knee and hip kinematics, the plantar pressure distribution and the isokinetic eccentric torque of the hip muscles in subjects with and without varus forefoot. Forty healthy sedentary subjects of both genders will participate in this study, divided in 4 groups: group of female subjects presenting compensated varus forefoot (n=10); group of female subjects presenting normal alignment of the forefoot (n=10); group of male subjects presenting compensated varus forefoot (n=10); group of male subjects presenting normal alignment of the forefoot (n=10). The kinematic assessment will be carried out with the Flock of Birds® equipment and the plantar pressure distribution will be assessed with the Pedar®-X System, during an anterior stair descent. The isokinetic eccentric torque of hip medial/lateral rotation and adduction/abduction will be assessed with an isokinetic dynamometer. Comparisons will be performed between the groups with and without varus forefoot. (AU)