Mononen Mika E, Jurvelin Jukka S, Korhonen Rami K
a Department of Applied Physics , University of Eastern Finland , P.O. Box 1627, FI-70211 Kuopio , Finland.
Comput Methods Biomech Biomed Engin. 2015;18(2):141-52. doi: 10.1080/10255842.2013.783575. Epub 2013 Apr 9.
Computational models can be used to evaluate the functional properties of knee joints and possible risk locations within joints. Current models with fibril-reinforced cartilage layers do not provide information about realistic human movement during walking. This study aimed to evaluate stresses and strains within a knee joint by implementing load data from a gait cycle in healthy and meniscectomised knee joint models with fibril-reinforced cartilages. A 3D finite element model of a knee joint with cartilages and menisci was created from magnetic resonance images. The gait cycle data from varying joint rotations, translations and axial forces were taken from experimental studies and implemented into the model. Cartilage layers were modelled as a fibril-reinforced poroviscoelastic material with the menisci considered as a transversely isotropic elastic material. In the normal knee joint model, relatively high maximum principal stresses were specifically predicted to occur in the medial condyle of the knee joint during the loading response. Bilateral meniscectomy increased stresses, strains and fluid pressures in cartilage on the lateral side, especially during the first 50% of the stance phase of the gait cycle. During the entire stance phase, the superficial collagen fibrils modulated stresses of cartilage, especially in the medial tibial cartilage. The present computational model with a gait cycle and fibril-reinforced biphasic cartilage revealed time- and location-dependent differences in stresses, strains and fluid pressures occurring in cartilage during walking. The lateral meniscus was observed to have a more significant role in distributing loads across the knee joint than the medial meniscus, suggesting that meniscectomy might initiate a post-traumatic process leading to osteoarthritis at the lateral compartment of the knee joint.
计算模型可用于评估膝关节的功能特性以及关节内可能的风险部位。目前具有纤维增强软骨层的模型无法提供有关步行过程中真实人体运动的信息。本研究旨在通过在具有纤维增强软骨的健康和半月板切除膝关节模型中输入步态周期的负荷数据，来评估膝关节内的应力和应变。利用磁共振图像创建了一个包含软骨和半月板的膝关节三维有限元模型。来自不同关节旋转、平移和轴向力的步态周期数据取自实验研究并输入到模型中。软骨层被建模为纤维增强的多孔粘弹性材料，半月板被视为横观各向同性弹性材料。在正常膝关节模型中，特别预测在负荷反应期间膝关节内侧髁会出现相对较高的最大主应力。双侧半月板切除术增加了外侧软骨的应力 、应变和流体压力，尤其是在步态周期站立阶段的前50%期间。在整个站立阶段，表层胶原纤维调节软骨的应力，尤其是在胫骨内侧软骨中。目前这个包含步态周期和纤维增强双相软骨的计算模型揭示了步行过程中软骨内应力、应变和流体压力随时间和位置的差异。观察到外侧半月板在膝关节负荷分布中比内侧半月板发挥更重要的作用，这表明半月板切除术可能引发一个创伤后过程，导致膝关节外侧间室发生骨关节炎。
