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

Effects of Prosthetic Alignment on Internal Contact Mechanical Characteristics of Intact Knee Joints for Transfemoral Amputees

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健全人及大腿截肢者在不同对线条件下行走时下肢运动及地面反作用力(ground reaction force,GRF)差异,并利用三维有限元模型分析接受腔内收和外展的异常对线情况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GRF第1峰值时刻膝关节接触力主要集中在内侧,在GRF第2峰值时刻接触力主要集中在外侧,而截肢者接触力在GRF的两个峰值时刻都集中在内侧。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。结论截肢者膝骨关节炎发病率高于健全人与其膝关节内侧长期过载有关,接受腔对线内收会增加大腿截肢者健侧膝关节骨关节疾病的风险,临床对线过程中应尽量避免过度内收。

Objective To study the effects of prosthetic alignment on internal contact mechanical characteristics of intact knee joint for transfemoral amputees. Methods The gait experiment of transfemoral amputees was performed under different alignment conditions,and the differences of lower limb motion and ground reaction force (GRF) were analyzed and compared with those of the non-amputees. The three-dimensional (30) finite element model of knee joint was build and used to analyze the effect of alignments of socket adduction and abduction on internal contact mechanical characteristics between femur cartilage,tibia cartilage and meniscus. Results For knee joint of the non-amputees,contact force was mainly concentrated on the medial sides at the moment of the first GRF peak,while contact force was mainly concentrated on the lateral sides at the moment of the second GRF peak. However,for intact knee joint of the transfemoral amputees,contact force was mainly concentrated on the medial side at the moment of two GRF peaks. The stress of the medial meniscus,contact force and contact area between the medial meniscus and cartilage all obviously increased under the alignment of 6° socket adduction. Conclusions Compared with non-amputees,the incidence of knee osteoarthritis (OA) in amputees was higher,which was related to the long-term overload of the medial knee joint. The alignment of socket adduction may increase the risk of knee OA in the intact side of transfemoral amputees. In clinic,excessive adduction of the socket should be avoided during prosthetic alignment.