Tang Jinghua, McGrath Michael, Hale Nick, Jiang Liudi, Bader Dan, Laszczak Piotr, Moser David, Zahedi Saeed
Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ, UK.
Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ, UK.
Med Eng Phys. 2017 Nov;49:131-139. doi: 10.1016/j.medengphy.2017.08.014. Epub 2017 Sep 15.
The bespoke interface between a lower limb residuum and a prosthetic socket is critical for an amputee's comfort and overall rehabilitation outcomes. Analysis of interface kinematics and kinetics is important to gain full understanding of the interface biomechanics, which could aid clinical socket fit, rehabilitation and amputee care. This pilot study aims to investigate the dynamic correlation between kinematic movement and kinetic stresses at the interface during walking tests on different terrains. One male, knee disarticulation amputee participated in the study. He was asked to walk on both a level surface and a 5° ramped surface. The movement between the residuum and the socket was evaluated by the angular and axial couplings, based on the outputs from a 3D motion capture system. The corresponding kinetic stresses at anterior-proximal (AP), posterior-proximal (PP) and anterior-distal (AD) locations of the residuum were measured, using individual stress sensors. Approximately 8° of angular coupling and up to 32 mm of axial coupling were measured when walking on different terrains. The direction of the angular coupling shows strong correlation with the pressure difference between the PP and AP sensors. Higher pressure was obtained at the PP location than the AP location during stance phase, associated with the direction of the angular coupling. A strong correlation between axial coupling length, L, and longitudinal shear was also evident at the PP and AD locations i.e. the shortening of L corresponds to the increase of shear in the proximal direction. Although different terrains did not affect these correlations in principle, interface kinematic and kinetic values suggested that gait changes can induce modifications to the interface biomechanics. It is envisaged that the reported techniques could be potentially used to provide combined kinematics and kinetics for the understanding of biomechanics at the residuum/socket interface, which may play an important role in the clinical assessment of prosthetic component settings, including socket fit quality.
下肢残肢与假肢接受腔之间的定制界面对于截肢者的舒适度和整体康复效果至关重要。分析界面的运动学和动力学对于全面理解界面生物力学很重要，这有助于临床接受腔适配、康复和截肢者护理。这项初步研究旨在调查在不同地形上行走测试期间，界面处运动学运动与动力学应力之间的动态相关性。一名男性膝关节离断截肢者参与了该研究。他被要求在平坦表面和5°斜坡表面上行走。基于三维运动捕捉系统的输出，通过角度和轴向耦合评估残肢与接受腔之间的运动。使用单独的应力传感器测量残肢前近端（AP）、后近端（PP）和前远端（AD）位置处的相应动力学应力。在不同地形上行走时，测量到约8°的角度耦合和高达32毫米的轴向耦合。角度耦合的方向与PP和AP传感器之间的压力差显示出很强的相关性。在站立阶段，PP位置的压力高于AP位置，这与角度耦合的方向有关。在PP和AD位置，轴向耦合长度L与纵向剪切之间也存在明显的强相关性，即L的缩短对应于近端方向剪切的增加。虽然不同地形原则上不影响这些相关性，但界面运动学和动力学值表明，步态变化可引起界面生物力学的改变。可以设想，所报道的技术可能潜在地用于提供运动学和动力学的组合，以理解残肢/接受腔界面处的生物力学，这可能在假肢部件设置的临床评估中发挥重要作用，包括接受腔适配质量。
