School of Mechanical Engineering, College of Engineering, University of Tehran, P.O.B. 11155-4563, Tehran, Iran.
School of Mechanical Engineering, College of Engineering, University of Tehran, P.O.B. 11155-4563, Tehran, Iran.
Med Eng Phys. 2019 Jul;69:123-133. doi: 10.1016/j.medengphy.2019.04.004. Epub 2019 Jun 5.
Drop foot is a nerve-muscle disorder that affects the muscles that lift the foot. The two main side effects of drop foot are slapping/kicking the foot after heel strike (foot) and dragging the foot during the swing (toe drag). Treatment methods such as ankle-foot orthoses (AFO) have some biomechanical benefits, but are not applicable to all walking conditions and cannot mitigate significant gait complications. This study introduces the design of a passive AFO system, which combines an ordinary AFO and a shape memory alloy (SMA) element. OpenSim was used to simulate patients with muscle weakness and to calculate the torque needed to imitate normal ankle joint stiffness. The calculated torque was then reproduced for different levels of muscle weakness by the superelasticity of SMAs. The study showed that the normal joint stiffness profile for each patient with a certain level of muscle weakness can be restored by designing a patient-specific orthosis.
足下垂是一种神经肌肉疾病，影响抬脚的肌肉。足下垂的两个主要副作用是脚跟触地后脚（foot）拍打/踢打和摆动时脚（toe drag）拖地。踝足矫形器（AFO）等治疗方法具有一些生物力学益处，但不适用于所有行走条件，也不能减轻严重的步态并发症。本研究介绍了一种被动 AFO 系统的设计，该系统结合了普通 AFO 和形状记忆合金（SMA）元件。OpenSim 用于模拟肌肉无力的患者，并计算模仿正常踝关节刚度所需的扭矩。然后，通过 SMA 的超弹性，为不同程度的肌肉无力再现计算出的扭矩。研究表明，通过设计特定于患者的矫形器，可以恢复具有一定肌肉无力水平的每位患者的正常关节刚度曲线。
