基于中医微观辨证运用疲劳断裂失效力学研究兔激素性股骨头坏死的塌陷机制

Fatigue fracture is the development of the material under the action of cyclic disturbances to crack or fully fracture.Collapse is a key outcome after the Osteonecrosis of the femoral head, and is the core judgment point for the success of conservative treatment and hip joint preserving surgery.As a mechanical behavior, the collapse of Osteonecrosis of the femoral head whose nature is the subchondral fracture is also applicable to fatigue fracture mechanics. Under the guidance of microcosmic syndrome differentiation theory of TCM, finite element analysis combined with the biomechanical experiment and fatigue test of animal model:(1) The material parameters and failure mode parameters of femoral head necrosis were obtained by biomechanical experiment. (2)The finite element analysis based on fracture failure theory to explore the establishment of the femoral head necrosis model and the mutual validation and optimization of the biomechanical experiments. (3) Fatigue failure analysis was performed by the fatigue testing machine to observe the microscopic failure and crack propagation during the dynamic fracture of the femoral head (4) The multivariate logistic regression analysis of the different microcosmic states of the necrotic area and the trend of its finite element analysis, as well as the key points in predicting the life of necrotic femoral head and seeking to resist collapse. To explore the collapse mechanical mechanism of femoral head necrosis, for its conservative treatment and hip joint preserving surgery to provide mechanical theoretical basis and new ideas.

疲劳断裂是材料在循环扰动作用下形成裂纹或完全断裂的发展过程。塌陷是股骨头坏死后的关键转归，且是保守治疗和保髋手术治疗能否成功的核心判断点。作为一种力学行为，本质为软骨下骨折的股骨头坏死塌陷同样适用于疲劳断裂失效力学研究。本项目拟在中医微观辨证理论的指导下，通过有限元分析结合动物模型的生物力学实验和疲劳试验：①通过生物力学实验探讨股骨头坏死区的材料参数以及失效模式参数；②通过断裂失效理论的有限元分析探讨股骨头坏死塌陷模型的建立以及与生物力学实验的相互验证和优化；③通过疲劳试验机进行疲劳断裂失效分析，观察股骨头动态断裂过程中的微观破坏和裂纹拓展以及与有限元塌陷模型的相互验证；④通过多元Logistic回归分析坏死区不同的微观状态与其有限元分析的塌陷趋势，以及预测坏死股骨头寿命和寻求抗塌陷的力学关键点。探明股骨头坏死塌陷的力学机制，为股骨头坏死的保守治疗和保髋手术治疗提供力学理论依据和新思路。

股骨头坏死是一种好发于青壮年的高度致残性和难治性疾病，塌陷是病情进展的分水岭，是股骨头坏死后的关键转归，塌陷防治是保髋治疗的核心，是保髋手术治疗能否成功的核心判断点。疲劳断裂是材料在循环扰动作用下形成裂纹或完全断裂的发展过程，塌陷作为一种力学行为，本质为软骨下骨折的股骨头坏死塌陷同样适用于疲劳断裂失效力学研究。本研究目的在中医微观辨证理论的指导下，通过基于断裂力学材料失效理论的有限元分析，创立股骨头九区划分法和建立股骨头坏死塌陷的有限元模型，探索股骨头坏死在不同微观状态下发生塌陷的相关生物力学机制；研究股骨头动态断裂过程中的微观破坏和裂纹以及循环应力下的疲劳寿命，预测坏死股骨头寿命，寻求抗塌陷的力学理论依据。研究表明当股骨头坏死涉及外侧柱和前侧柱时，出现塌陷的风险增加，可能短时间内会塌陷，并且塌陷程度严重，相比之下，在中柱发生坏死时，塌陷的风险减小，较晚出现塌陷，塌陷程度不重。股骨头软骨下皮质骨的完整可有效分散应力，当股骨头坏死后，由于股骨头坏死区形态的改变，使其无法有效传递载荷，正常载荷的传递受阻，导致坏死边界区硬化带的产生，该处产生应力集中，疲劳加载下该处寿命减少，导致软骨下皮质骨裂纹的萌生，循环应力加速裂纹的扩展，最终导致软骨下骨折的发生，加速股骨头塌陷。本研究进一步明确了前外侧在对抗股骨头坏死塌陷的重要地位，重建前外侧柱的生物力学结构和载荷传递模式，维持前外侧柱的完整性是防治股骨头塌陷重点，为股骨头坏死的保守治疗和保髋手术治疗提供力学理论依据。