The Correction Effects On Gait Of Orthopaedic Insole On Flat-foot And Varus Knee

Purpose:Flat foot and varus knee are common lower extremities deformity. Serious deformities can cause arthritis or muscle dysfunction in the lower extremities and even low-back. This study will explore the similarities and differences of gait between flatfoot and varus knee subjects and normal population, and their subjective feelings and the biomechanical characteristics changes of gait after the use of orthopaedic insole. This can help to study the effect and mechanism of orthopaedic insole in redressing the flat feet and varus knee, to provide better clinical services, and reference information of selecting orthopaedic appliances for people with such deformities.Methods:Twelve male flatfoot,12varus knee and8normal subjects were sinvolved in this study. In the first test, the gait cycle characteristics of all subjects’without insoles and all subjects without mormal group with particular insloes were collected by infrared high-speed motion capture system, surface EMG test system and plantar pressure insoles test system. In the following two months after the first test,6members of either the flatfoot or the varus knees subjects, respectively, were selected to wear orthopaedic insoles as padded group, and the rest as control groups, and all the subjects except the normal group had track test of their gait by Tekscan plantar pressure insoles test system. The subjects of padded group filled the wearing evaluation form in each test. After all the tests, Visual3D and Matlab program and etc. were used to process the collected data. The gait cycle kinematics, the lower extremity coupling mechanism, the muscle activate order and duration, and the plantar pressure distribution were calculated. The statistic analysis were processed by SPSS. One-way ANOVA, paired t-test, repeated measures, and Pearson simple relative test were used to evaluate the differences and correlations among all the groups. All the significant levels were set at p<0.05.Results:In the first test, the relative plantar flexion strength of the flatfoot and varus knee group were significantly reduced when padded. The center of force curve was whole relocated to lateral side. In the tracking test, the plantar flexion force of padded flatfoot group was increasing with time when not padded. The pressure of MF was in a trend of decreasing of all flatfoot groups; The pressure of M1-2in the padded group showing a decreasing trend when not padded. At the moment of heel contact, the ankle dorsiflexion angle of flatfoot group was93.1°without padded increased to99.3°(p<0.05) when padded, which was closer to the normal group; the midfoot plantar flexion angle of varus knee group was-30.6°when without padded, increased to-41.7°(p<0.05) when padded. The excursion ratio of ankle eversion and tibial internal rotation of the flatfoot group when padded in mid and late stance phase were closer than when not padded to the normal group; in the varus knee groups, the internal/external rotation angle of knee in the early and mid stance phase were bigger than that of the normal group, which increased when padded. The time difference of knee flexion and ankle pronation in the mid stance phase of the flatfoot group was decreased when padded. Conclusions:1, The thopaedic insole gave the flat foot group better feeling, but the subjective feeling in the varus knee group vatied.2, The flat foot and the varus knee groups did domenstrated different gait characteristics from the normal group. The immediate effect of thopaedic insole on the flat foot group was improving the gait characteristics, and changing the characteristics of the varus knee group.3The long term effect of thopaedic insole was:increasing the plantar flexing strength, increasing the support under the lateral longitudinal arch, and decreasing the ankle pronation.