The Effect of Orthotic Shoe Inserts in the flatfoot

摘要

Flat foot deformity often treated with orthotic shoe inserted in clinically. These devices are designed to provide stability and realign the foot arch. They have been shown to be successful treatment to reduce the patients' symptom. Although orthotics shoes inserts is widely used in the treatment to the flatfoot, our understanding of the biomechanical effects is not clear. The purpose of this study was to evaluate the effects of shoes and foot insoles on gait patterns of the patients with flatfoot during the stance phase of level walking. Eleven adults with flatfoot deformity were recruited. Shoes and insoles were manufactured for each participant. Each participant was measured under three test conditions with three successful repetitions each. The test conditions included: walking barefoot (WB), walking with shoes (WS), and walking with shoes and insoles (WSI). Fifteen spherical retro-reflective markers for 7 lower body segments with Helen Hayes set were attached on subjects' selected anatomic landmarks. An eight-camera Motion Analysis Eagle Digital System was used to collect the trajectories of reflective markers. Two Kistler force plates were synchronized with the motion system to measure the ground reaction force during walking. Three-dimensional trajectories were reconstructed using EVaRT 4.2 software. The joint angles were determined from the anatomical and segmental coordinate systems. Data on body segment motions and foot/floor reactions were processed with the computer software OrthoTrak 5.0, and the angle, force and moment were taken for analysis. The results showed that WSI increasd the peak knee flexion angle, ankle dorsiflexion angle and reduced the peak ankle plantarflexion. The peak knee varus moment and ankle dorsiflex moment were significantly gretater for WSI. The peak ankle plantarflex moment was significantly smaller for WSI.The results indicated that the greater effects of the orthoses were on the ankle joint, and the minimal effect on the knee and hip joint. Our finding suggested that the symptoms on the ankle joint in the pes planus relief with the use of such device could due to the siginificantly changes in ankle plantar/dorsiflexion angle and moment. The results of the present study show no significant difference in the ankle pronation angle and moment. Thus, it imply that the benefits of the foot orthoses to realign the pronated position of patients with flat foot are not supported. The reason that there is no statistical difference in the ankle pronation angle and moment might be due to our evaluation of the immediate effects. Therefore, the further study of the long term effect of orthotic intervention is necessary to investigate what is the foot orthoses mechanical efficiency over time and adapted mechanism to the lower extremity in the flat foot.