Michigan State University Mechanical Engineering, 428 S. Shaw Lane, East Lansing, MI 48824, United States.
Department of Mechanical Engineering, Michigan State University, 428 S. Shaw Lane, East Lansing, MI 48824, United States.
Med Eng Phys. 2019 Sep;71:102-107. doi: 10.1016/j.medengphy.2019.07.002. Epub 2019 Jul 20.
Patients with transtibial amputation experience ulcers on their residual limb. The loading between the device and underlying material plays a role in loads transmitted to the skin. The objective was to evaluate normal and shear forces at the socket/liner interface during walking. A 53 year old male (85.45 kg and 177.8 cm) with a transtibial amputation participated in this case study. A transtibial prosthesis was instrumented with a load cell to measure normal and shear forces at the socket interface. Three conditions were evaluated during walking: gel liner, additional three ply sock and a hole in the gel liner. Shear and normal forces were highest with the addition of a three ply. Longitudinal shear stresses ranged from 0.4-7.66 kPa, transverse shear stresses ranged from 0.01-7.79 kPa and normal stresses ranged from 2.7-61.9 kPa. Increased shear and normal forces can cause a significant decrease in blood perfusion, linked to an increased risk of ulcer formation. Experimental force results are also important for future work involving finite element modeling of the skin/liner/device interface.
小腿截肢患者的残肢上会出现溃疡。装置和底层材料之间的负载在传递到皮肤的负载中起着作用。目的是评估行走过程中在插座/衬里界面处的正常和剪切力。本案例研究纳入了一名 53 岁男性（85.45kg 和 177.8cm），他患有小腿截肢。在小腿假肢上安装了一个测力传感器，以测量插座接口处的正常和剪切力。在行走过程中评估了三种情况：凝胶衬里、额外的三层袜子和凝胶衬里上的一个孔。增加三层袜子时，剪切力和正压力最大。纵向剪切应力范围为 0.4-7.66kPa，横向剪切应力范围为 0.01-7.79kPa，法向应力范围为 2.7-61.9kPa。增加的剪切力和正压力会导致血液灌注显著减少，从而增加溃疡形成的风险。实验力结果对于未来涉及皮肤/衬里/装置界面的有限元建模的工作也很重要。
