Department of Ergonomics, School of Public Health and Safety, Shahid Behehsti University of Medical Sciences, 1983969411, Tehran, Iran; Robotics, Design and Optimisation, Mechanical Engineering, University of Leeds, School of Mechanical Engineering, Leeds LS2 9JT, United Kingdom.
Faculty of Engineering, Ain Shams University, Cairo, Egypt.
Med Eng Phys. 2019 Jun;68:46-56. doi: 10.1016/j.medengphy.2019.03.014. Epub 2019 Apr 9.
The relationship between the functional loading rate and heel velocities was assessed in an active unilateral transfemoral amputee (UTFA) for adaptation to six different commercial prosthetic knees.
To Investigate the short-term process of adaptability for UTFA for two types of prosthetic knees were evaluated, based on the correlation between heel vertical velocity and transient loading rate.
The loading rate was calculated from the slope of ground reaction forces (GRF) and the corresponding time. The heel velocities and GRF were obtained by a motion analysis system.
Biomechanical adaptation was evident following a short period of prosthetic knee use based upon the mean transient impact (loading rate) and the heel vertical velocity in slow, normal and fast walking. Trend lines of transient impact versus vertical heel velocity for a set of actively controlled variable damping (microprocessor) and mechanically passive prosthetic knees were all negatively correlated, except for an amputated leg during normal pace and healthy leg during fast pace. For an amputee to adapt well to a prescribed prosthesis excellent coordination between the intact and amputated limbs is required to control placement of the amputated leg to achieve a gait comparable to healthy subjects.
There are many factors such as the hip, knee flexion/extension and the ankle plantarflexion/dorsiflexion contributing to the control of the transient impact of an amputee during walking. Therefore, for enhanced control of a prosthetic knee, a multifaceted approach is required. This study showed that UTFA adaption to different prosthetic knees in the short term with slower than self-selected speed is completely achievable based on the negative correlation of ground reaction forces versus linear velocity. Reduced speed may provide the prosthetists with the vision of the amputees' progression of adaptation with a newly prescribed prosthetic knee.
在一位活跃的单侧股骨截肢者（UTFA）中，评估了功能加载率与脚跟速度之间的关系，以适应六种不同的商业假肢膝关节。
根据脚跟垂直速度与瞬态加载率之间的相关性，研究 UTFA 对两种类型假肢膝关节的短期适应过程。
通过运动分析系统获得脚跟速度和地面反作用力（GRF）。加载率是通过 GRF 的斜率和相应的时间计算得出的。
假肢膝关节使用短时间后，基于慢走、正常行走和快走时的平均瞬态冲击（加载率）和脚跟垂直速度，生物力学适应性明显。主动控制可变阻尼（微处理器）和机械被动假肢一组的瞬态冲击与垂直脚跟速度的趋势线均呈负相关，除了正常步速下的截肢腿和快速步速下的健康腿。为了使截肢者很好地适应规定的假肢，需要完好和截肢肢体之间的出色协调，以控制截肢腿的位置，以实现与健康受试者相当的步态。
在行走过程中，有许多因素会影响截肢者瞬态冲击的控制，例如臀部、膝关节的屈伸和踝关节的跖屈/背屈。因此，需要采用多方面的方法来增强对假肢膝关节的控制。本研究表明，UTFA 以比自我选择速度慢的速度在短期内适应不同的假肢膝关节是完全可行的，这是基于地面反作用力与线性速度之间的负相关关系。降低速度可以为假肢技师提供新规定的假肢膝关节的截肢者适应进展的视野。
