Numerical analysis on damage evolution of rectangular articular cartilage with micro-defect under compressive loads / 医用生物力学

Objective To study the damage propagation and evolution mechanism of cartilage under compressive loads.Methods The fiber-reinforced porous elastic model of cartilage with micro-defect was established by using finite element method,and the process of damage evolution under compressive loads was simulated and analyzed with parameters.The patterns of stress and strain distributions on cartilage matrix and collagen fiber at different damage extension stages were obtained.Results The strain in the surface and forefront of cartilage damage increased significantly with the increase of compression displacement,and they were obviously in positive correlation;in the process of damage evolution,there was a trend that cartilage extended to the deep and both sides simultaneously;cracks and damage in cartilage extended preferentially along the fiber tangent direction.With the aggravation of cartilage damage,the lateral extension speed was significantly faster than the longitudinal extension speed.Conclusions The process of cartilage damage extension has a close relationship with the distribution of fibers.The damages in matrix and fiber promote each other.The evolution speed and degree of cartilage vary constantly in different layers and at different stages.These results can provide the qualitative reference for prediction and repair of cartilage damage,as well as the theoretical basis for explaining pathological phenomena of damage degeneration and its clinic treatment.

Numerical analysis on damage evolution of rectangular articular cartilage with micro-defect under compressive loads / 医用生物力学

Objective To study the damage propagation and evolution mechanism of cartilage under compressive loads.Methods The fiber-reinforced porous elastic model of cartilage with micro-defect was established by using finite element method,and the process of damage evolution under compressive loads was simulated and analyzed with parameters.The patterns of stress and strain distributions on cartilage matrix and collagen fiber at different damage extension stages were obtained.Results The strain in the surface and forefront of cartilage damage increased significantly with the increase of compression displacement,and they were obviously in positive correlation;in the process of damage evolution,there was a trend that cartilage extended to the deep and both sides simultaneously;cracks and damage in cartilage extended preferentially along the fiber tangent direction.With the aggravation of cartilage damage,the lateral extension speed was significantly faster than the longitudinal extension speed.Conclusions The process of cartilage damage extension has a close relationship with the distribution of fibers.The damages in matrix and fiber promote each other.The evolution speed and degree of cartilage vary constantly in different layers and at different stages.These results can provide the qualitative reference for prediction and repair of cartilage damage,as well as the theoretical basis for explaining pathological phenomena of damage degeneration and its clinic treatment.

Numerical analysis on damage evolution of rectangular articular cartilage with micro-defect under compressive load / 医用生物力学

Objective To study the damage propagation and evolution mechanism of cartilage under compressive load. Methods The fiber-reinforced porous elastic model of cartilage with micro-defect was established by using finite element method, and the process of damage evolution under compressive load was simulated and analyzed with parameters. The patterns of stress and strain distributions on cartilage matrix and collagen fiber at different damage extension stage were obtained. Results The strain in surface and the forefront of cartilage damage increased significantly with the increase of compression displacement, and they were obviously in positive correlation; in the process of damage evolution, there was a trend that cartilage extended to the deep and both sides simultaneously; cracks and damage in cartilage extended preferentially along the fiber tangent direction. With the aggravation of cartilage damage, the lateral extension speed was significantly faster than the longitudinal extension speed. Conclusions The process of cartilage damage extension has a close relationship with the distribution of fibers. And the damage in matrix and fiber promote each other. The evolution speed and degree of cartilage vary constantly in different layers and at different stages. These results can provide the qualitative reference for prediction and repair of cartilage damage, as well as the theoretical basis for explaining clinical pathological phenomena of damage degeneration and treatment.

Biomechanical research progress on minimally invasive surgical repair of pectus excavatum / 医用生物力学

开展漏斗胸微创矫形手术的生物力学研究以及阐述矫形机制对于提高矫形手术水平、开展个性化手术治疗、发展新的矫形手术方法和扩展微创矫形手术的应用范围具有重要意义。漏斗胸微创矫形手术已经成功用于儿童的漏斗胸矫形，但是成人漏斗胸矫形手术的应用还未普及。面对漏斗胸矫形可能会加重脊柱侧弯的风险，医生被迫放弃手术，致使部分漏斗胸合并脊柱侧弯的患者终生不能得到治疗。总结漏斗胸微创矫形手术的生物力学研究进展，包括胸廓模型的三维重建、矫形模型的应用、矫形过程的数值模拟以及数值模拟结果在临床的应用。结合成人漏斗胸矫形数值模拟的特点提出解决方法，并针对漏斗胸的生物力学研究现状提出需要解决的问题，如计算模型需要考虑主要肌肉、椎间盘、前后纵韧带、椎体横凸棘间韧带和棘上韧带，验证数值计算结果的实验研究方法等。

Advances of mechanical conditions in engineering cartilage tissue / 医用生物力学

There are many physical factors affecting the development of cartilage tissue,the mechanical con-dition is the main important one that particularly act.The mechanical conditions used in engineering cartilage tissue,such as compressive and shear force,fluid flow,hydrostatic pressure and tissue deformation or with some of them combined,were reviewed.From the standpoint of bionics,the mechanical environments ap-plied on tissue engineering should work in three aspects:providing adequately mechanical stimuli to the cells seeded in 3-D scaffold;ensuring the efficient mass-transport of the nutrients and waste products in the cells:promoting the development of functionally extracellular matrix in 3-D scaffold.The mechanical environments currently used only represented the part of mechanical conditions of in vive articular cartilage will be reviewed.In our view that rolling depression load may achieve the fit mechanical environment for cultivation of functional cartilage constructs in vitro.

Advances of mechanical conditions in engineering cartilage tissue / 医用生物力学

There are many physical factors affecting the development of cartilage tissue,the mechanical con-dition is the main important one that particularly act.The mechanical conditions used in engineering cartilage tissue,such as compressive and shear force,fluid flow,hydrostatic pressure and tissue deformation or with some of them combined,were reviewed.From the standpoint of bionics,the mechanical environments ap-plied on tissue engineering should work in three aspects:providing adequately mechanical stimuli to the cells seeded in 3-D scaffold;ensuring the efficient mass-transport of the nutrients and waste products in the cells:promoting the development of functionally extracellular matrix in 3-D scaffold.The mechanical environments currently used only represented the part of mechanical conditions of in vive articular cartilage will be reviewed.In our view that rolling depression load may achieve the fit mechanical environment for cultivation of functional cartilage constructs in vitro.