Center of Excellence for Prosthetic and Orthopedic Implant, Chulalongkorn University, Bangkok, 10330, Thailand.
Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Sci Rep. 2023 Dec 20;13(1):22809. doi: 10.1038/s41598-023-49879-4.
A conventional 4-bar polycentric knee and solid ankle cushion heel foot (SACH foot) have been commonly used in developing countries. However, they cannot perform stance-phase knee flexion, which makes a person with an amputation walk unnaturally and with less stability. This research proposes a novel design of a 4-bar polycentric knee with stance-phase knee flexion ability (4BSF), which can perform both stance and swing-phase knee flexion, like able-bodied gait. In the proposed conceptual design, the instantaneous center of rotation (ICR) path is repositioned during the stance phase. The ICR was placed in front of the ground reaction force (GRF) to initiate knee flexion during the loading response. The prototype was validated by a single-subject pilot study at the Gait analysis laboratory. The results showed that a person with an amputation walks with stance-phase knee flexion using the proposed 4BSF. The maximum knee flexion angle is more than 10° during the stance phase. Furthermore, when the 4BSF was used with a SACH foot, the amount of time to achieve the foot flat was shorter, and the foot flat duration time was twice as long as the conventional 4-bar polycentric knee.
传统的四连杆多中心膝关节和实心踝垫脚跟脚（SACH 脚）在发展中国家被广泛使用。然而，它们无法在站立阶段进行膝关节弯曲，这使得截肢者的行走不自然且稳定性较差。本研究提出了一种具有站立阶段膝关节弯曲能力的新型四连杆多中心膝关节（4BSF）设计，它可以像健全人一样进行站立和摆动阶段的膝关节弯曲。在提出的概念设计中，瞬时旋转中心（ICR）路径在站立阶段重新定位。ICR 放置在地面反作用力（GRF）的前面，以在负荷响应期间启动膝关节弯曲。该原型在步态分析实验室进行了单例初步研究。结果表明，使用所提出的 4BSF，截肢者可以在站立阶段进行膝关节弯曲。在站立阶段，最大膝关节弯曲角度超过 10°。此外，当 4BSF 与 SACH 脚一起使用时，达到脚平的时间更短，脚平持续时间是传统四连杆多中心膝关节的两倍。
