Zanjani-Pour Sahand, Giorgi Mario, Dall'Ara Enrico
Department of Oncology and Metabolism, Mellanby Center for Bone Research, University of Sheffield, Sheffield, United Kingdom.
Insigneo Institute for in Silico Medicine, University of Sheffield, Sheffield, United Kingdom.
Front Bioeng Biotechnol. 2020 Oct 15;8:558815. doi: 10.3389/fbioe.2020.558815. eCollection 2020.
Osteoarthritis is the most common musculoskeletal disabling disease worldwide. Preclinical studies on mice are commonly performed to test new interventions. Finite element (FE) models can be used to study joint mechanics, but usually simplified geometries are used. The aim of this project was to create a realistic subject specific FE model of the mouse knee joint for the assessment of joint mechanical properties. Four different FE models of a C57Bl/6 female mouse knee joint were created based on micro-computed tomography images of specimens stained with phosphotungstic acid in order to include different features: individual cartilage layers with meniscus, individual cartilage layers without meniscus, homogeneous cartilage layers with two different thickness values, and homogeneous cartilage with same thickness for both condyles. They were all analyzed under compressive displacement and the cartilage contact pressure was compared at 0.3 N reaction force. Peak contact pressure in the femur cartilage was 25% lower in the model with subject specific cartilage compared to the simpler model with homogeneous cartilage. A much more homogeneous pressure distribution across the joint was observed in the model with meniscus, with cartilage peak pressure 5-34% lower in the two condyles compared to that with individual cartilage layers. In conclusion, modeling the meniscus and individual cartilage was found to affect the pressure distribution in the mouse knee joint under compressive load and should be included in realistic models for assessing the effect of interventions preclinically.
骨关节炎是全球最常见的导致肌肉骨骼功能障碍的疾病。通常在小鼠身上进行临床前研究以测试新的干预措施。有限元（FE）模型可用于研究关节力学，但通常使用简化的几何形状。本项目的目的是创建一个真实的小鼠膝关节特定个体有限元模型，以评估关节力学性能。基于用磷钨酸染色的标本的微型计算机断层扫描图像，创建了C57Bl/6雌性小鼠膝关节的四种不同有限元模型，以纳入不同特征：带有半月板的单个软骨层、没有半月板的单个软骨层、具有两种不同厚度值的均匀软骨层以及两个髁厚度相同的均匀软骨。对它们在压缩位移下进行了分析，并在0.3 N反作用力下比较了软骨接触压力。与具有均匀软骨的更简单模型相比，具有特定个体软骨的模型中股骨软骨的峰值接触压力低25%。在有半月板的模型中观察到整个关节的压力分布更加均匀，与具有单个软骨层的模型相比，两个髁中的软骨峰值压力低5-34%。总之，发现对半月板和单个软骨进行建模会影响小鼠膝关节在压缩载荷下的压力分布，并且在临床前评估干预效果的真实模型中应包含这些因素。
