工程化软骨几何形状对缺损修复区力学行为的影响

摘要

BACKGROUND: Uncertainty of repairing articular cartilage defects is highly associated with the mechanical behaviors of the defected area, and the mechanical environment varies with the defect shape, depth and load. OBJECTIVE: To study the mechanical behaviors of articular cartilage defects under physiological load by finite element analysis. METHODS: The axisymmetric model of articular cartilage injury and repair based on transversely isotropy was established using ABAQUS software. The mechanical behaviors of the defect zone repaired with different repair shapes (cylindrical, frustum of a cone, orthorhombic prism, elliptical column) and depths of tissue-engineered cartilage under compressive load were analyzed. RESULTS AND CONCLUSION: The simulation results showed that there were significant differences in the mechanical behaviors of the defect area repaired with tissue-engineered cartilage in different shapes and depths. The stress concentration was the most obvious at the middle-layer defect repair, and the stress distribution was more reasonable at the deep (whole) layer defect repair. Furthermore, the distribution of the stress field and the liquid flow field at the cylinder-shaped tissue-engineered cartilage repair was the closest to the normal cartilage. That is to say, the tissue-engineered cartilage in cylinder or frustum-cone shape is recommended to repair cartilage defect. Importantly, the middle-layer repair is inadvisable.%背景:关节软骨损伤修复结果的不确定性与修复区的力学行为有关,缺损修复的形状、层深及载荷特性均不同程度地改变修复区的力学环境.目的:通过有限元仿真分析在生理载荷作用下关节软骨缺损修复区的力学行为.方法:应用有限元软件ABAQUS建立基于横观各向同性的关节软骨损伤与修复的轴对称模型.分析在压缩载荷作用下,软骨不同修复形状(圆柱、圆台、正棱柱、椭圆柱形)和深度对缺损软骨修复区力学行为的影响.结果与结论:①模拟结果表明,不同形状、层深的工程化软骨对软骨修复区力学行为影响规律不同;②中间层缺损修复时应力集中现象最显著,深(全)层缺损修复时应力分布较合理;③圆柱形工程化软骨修复时的应力场及液相流场分布规律与无损软骨最为接近;临床上,可以选用圆柱形或圆台形工程化软骨进行修复,且尽量避免中间层修复.