Development of Automated Techniques for Modelling Cartilage Morphology and Mechanics

提案动机：我们的研究小组开发了针对特定主题的骨骼、软组织和关节有限元模型。这些模型使用临床成像工具(如CT和MRI)来定义组织几何形状和材料属性。使用这些工具，我们最近观察到膝骨性关节炎(一种令人衰弱的关节疾病)患者和膝盖健康的人在骨应力方面的显著差异。这些发现导致与多中心骨关节炎研究(MOST)的研究人员合作，研究了2100名志愿者(4200膝)在骨关节炎疾病进展的不同阶段(健康、疾病早期、疾病晚期)进行CT和MRI纵向评估时的骨骼应力和应变。我们的模型准确地预测了骨骼的力学行为。目前还不清楚他们对软骨力学行为的预测有多好。[目标1]在我们的有限元模型中，[目标1]建立有效的软骨厚度、体积、面积以及接触面积的表达式；[目标2]验证有限元模型提供的软骨硬度和接触应力的无创性预测；[目标3]表征接触应力以及软骨厚度、体积、表面积和接触面积的无创性估计的测量误差。这项研究的进展将支持着眼于开发一个完整的膝关节有限元模型的长期目标，该模型包括骨、软骨和所有支撑结构(半月板、韧带)。影响：这项研究将使骨、软骨和关节的大规模有限元建模成为可能，从而推动特定学科的有限元建模更接近临床应用和实践。这项研究将培养高素质的人才，以便在自然科学和工程研究以及高度需要发展的技术技能的行业中从事职业。此外，我们将与临床研究人员合作，应用所开发的技术，进一步了解力学在退行性关节疾病的病因、预后和预防中的作用。这些技术和相关知识可以为开发新的疾病早期检测诊断工具提供基础。

PROPOSAL MOTIVATION: Our research group develops subject-specific finite element models of bone, soft tissue and joints. These models employ clinical imaging tools (like CT and MRI) to define tissue geometry and material properties. Using these tools, we recently observed marked differences in bone stress between people affected with knee osteoarthritis, a debilitating joint disease, and individuals with healthy knees. These findings led to a collaboration with researchers from the Multicenter Osteoarthritis Study (MOST) to study bone stress and strain in 2100 volunteers (4200 knees) longitudinally evaluated with CT and MRI at different stages of osteoarthritis disease progression (healthy, early disease stage, late disease stage). Our models accurately predict bone mechanical behavior. It is unclear how well they predict cartilage mechanical behavior. OBJECTIVES: The proposed research program aims to advance our finite element modeling technique by addressing the following short term research objectives, with a focus on the patellofemoral joint (region under kneecap): [OBJECTIVE 1] Develop valid representations of cartilage thickness, volume and area, as well as contact area, within our finite element model; [OBJECTIVE 2] Validate non-invasive predictions of cartilage stiffness and contact stress offered by the finite element model; [OBJECTIVE 3] Characterize measurement errors for non-invasive estimates of contact stress as well as cartilage thickness, volume, surface area and contact area. Developments arising from this research will support long-term objectives focused on developing a complete finite element model of the knee incorporating bone, cartilage and all supportive structures (menisci, ligaments). IMPACT: This research will enable large scale finite element modelling of bone, cartilage and articulating joints, thereby advancing subject-specific finite modelling closer to clinical application and practice. This research will train highly qualified personnel to pursue careers in natural science and engineering research and industry where developed technical skills are highly sought. In addition, we will collaborate with clinical researchers to apply the developed techniques to further understanding of the role of mechanics in etiology, prognosis and prevention of degenerative joint disease. These techniques, and related knowledge, can provide bases for developing new diagnostic tools for early disease detection.