Biomechanical modelling for quantitative assessment of gait kinematics in drop foot patients with ankle foot orthosis

Ankle-Foot Orthosis (AFO) is a brace that is worn on the lower leg and foot to support and hold the foot and ankle in the correct position during movement. AFOs are used to control the movement of drop foot, which is the inability to lift the front part of the foot. It is of great interest to learn more about the limitations of drop foot syndrome in gait biomechanics, and how the use of AFOs can improve these aspects. Gait analysis offers a powerful tool for analysing the biomechanics of subjects' gait. In this study we integrate data from markers of an optoelectronic gait analysis system with a customized biomechanical model to simulate and analyse the walking biomechanics of the patient in order to further explore his gait features and evaluate the AFO performances during walking. The analysis was carried out on a group of 19 patients suffering drop foot syndrome, using the Codivilla spring orthosis, by means of ANOVA statistical test, to verify the differences among limbs and the effects of the use of the AFO. Results show a significant difference in mean ankle angle and angle at heel strike between the paretic and contralateral limb, and that the use of the AFO significantly reduce the range of motion of ankle joint in the affected limb. Moreover this work analyses the subtalar angle, proving that the drop foot syndrome causes the prevalence of eversion of subtalar joint in the paretic limb during walking, and that the considered AFO does not produce significant improvements on this kinematics.