1.National Research Center for Rehabilitation Technical Aids;2.School of Biological Science and Medical Engineering ,Beihang University;3.Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability;4.Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University,;5.Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs;6.Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University
目的 研究假肢对线对大腿截肢者健侧膝关节内部接触力学特性的影响。 方法 通过步态实验分析了健全人及大腿截肢者在不同对线条件下行走时的下肢运动及地面反力,并利用三维有限元模型分析了不同力的作用方式对膝关节内部股骨软骨、胫骨软骨与半月板之间接触力学特性的影响。 结果 健全人在步态周期中膝关节内外侧的接触力相对均衡,而截肢者的接触力在整个步态周期都集中在内侧。接受腔对线内收6°会导致膝关节内侧应力、接触力、接触面积均明显增大。结论 本文一定程度上解释了大腿截肢者穿戴假肢及不同对线对健侧膝关节内部接触力学特性的影响,以及与膝关节炎症、损伤的相关性,并提出了假肢对线的建议。
Objective This paper aimed to study the effect of prosthetic alignment on the internal contact mechanical characteristics of intact knee joint for transfemoral amputees. Methods In this study, the gait experiment of transfemoral amputees was performed under different alignment conditions, the data of lower limb motion and ground reaction force (GRF) were analyzed and compared with those of the non-amputees. A three-dimensional finite element model of knee joint was build and used to analyze the effect of different loading modes on the internal contact mechanical characteristics between femur cartilage, tibia cartilage and meniscus. Results For the knee joint of the non-amputees, the contact force was mainly concentrated on the medial sides at the moment of the first GRF peak, while the contact force was mainly concentrated on the lateral sides at the moment of the second GRF peak. However, for the intact knee joint of the transfemoral amputees, the contact force was mainly concentrated on the medial side during the gait cycle. The Mises stress of the medial meniscus, the contact force and contact area between the medial meniscus and cartilage were all obviously increased under the alignment of 6° socket adduction. Conclusions To some extent, this study explained what changes occur in the internal contact of the intact knee due to amputation or abnormal alignment, and how these changes might be related to the development of knee OA. Then, based on the biomechanical analysis, some suggestions about prosthetic alignment were proposed.