基于细观结构的韧带机械损伤力学特性及其对人体膝关节软骨磨损影响的研究

Knee osteoarthritis commonly occurs in the elderly population. It endangers human health and brings the heavy economic and social burden. Anterior cruciate ligament insufficiency and the resulting instability and mechanical change are main factors to degeneration of articular cartilage and osteoarthritis. Our objective is to quantitative description of the mechanical properties of ligament with injury and the wear of the articular cartilage based on both experimental and theoretical models using macro- and meso combined methods. First mechanical properties and wear test performed using human knee cartilage specimen and complete knee cartilage under various working conditions to get cartilage material data and wear data.The wear models are explored to discribe the relations of cartilage wear and mechanical multivariate. Secondly, the ligament macro and meso tensile test carried out to correct volume compressible item. The meso-structure key parameters of type I and type III collagen fibers are analyzed so as to characterize the ligament mechanical properties. The macro-constitutive relation of ligament containing the meso-structure key parameters considering the ligament various condistions of injury are studied and verified experimently. Finally, we will establish the knee joint three-dimensional finite element model with ligament injury and simulate the articular cartilage wear characteristics based on artilage wear models under typical action. Combined with clinical statistical analysis, our research provides the mechanical reference for the prevention and treatment of knee osteoarthritis.

膝关节骨关节炎普遍发生于中老年人群中，危害人体健康并带来沉重的经济和社会负担，膝关节韧带损伤引起的韧带功能障碍是加剧关节软骨磨损导致骨关节炎恶化的重要因素。本项目提出从实验和理论建模两方面，采用宏细观结合的方法量化表征韧带损伤力学特性及与膝关节软骨磨损损伤的关系。项目首先进行人体关节软骨样本块和完整膝关节软骨的力学性能及磨损实验，获得软骨材料及磨损数据，探究描述软骨磨损的建模方法，构建含多力学变量的软骨磨损损伤模型；其次开展韧带宏观和细观拉伸实验，提出韧带宏观本构关系中体积可压缩项描述方法，研究表征韧带力学行为的I型和III型胶原纤维细观结构关键参数，建立含细观结构参数的韧带宏观本构关系并进行实验验证。通过分析韧带损伤后胶原纤维等参数的变化，构建韧带损伤发生、扩展等阶段的韧带本构。最后建立含韧带不同损伤情况的膝关节有限元模型，研究典型动作下关节软骨磨损特性，为膝关节炎的防治提供力学基础。

膝关节骨关节炎普遍发生于中老年人群中，危害人体健康并带来沉重的经济和社会负担，项目从理论和实验两方面对韧带特性和关节软骨磨损特性进行研究，取得的主要成果有：在韧带特性方面：分析了韧带中胶原类型的分布情况以及与纤维直径的相关关系,得到了胶原类型是一种不同于纤维直径的表征韧带微观特征的变量。构建了含细观结构参数的膝关节韧带宏观本构，建立了完备膝关节力学分析模型，得到了韧带变化过程中如生长、衰老、损伤等的本构化描述方法，实现了韧带变化对膝关节稳定性及组织受力的影响分析。在软骨磨损特性方面：自主研发了实验载荷、屈伸角和频率等运动参数可控的大鼠膝关节整体式体外磨损实验装置，实现不同运动形式对于软骨磨损的影响实验；自主研究搭建了进行定载/循环载荷加载同时进行往复与扭转复合运动的样块磨损平台。完成了动物完整关节、标准样块儿实验，从软骨力学性能、软骨化学成分和软骨中胶原纤维网络结构三方面对磨损前后软骨性能进行全面的定量或定性研究。自主构建了超声检测平台和数据采集系统并提出定量新指标，利用超声波对关节软骨的退化进行综合定量检测。研究结果表明：经过循环载荷磨损实验后，试样胫骨软骨卸载刚度减小的幅度比定载荷实验组大。关节外侧半月板的胶原微结构变化先于胫骨外侧软骨。软骨沿深度方向胶原和多糖蛋白含量发生变化而软骨中层的胶原微结构可以先于表层发生变化。研究工作对软骨磨损退化的机制、防范与治疗提供了基础。