BIOMECHANICAL MODULATORS OF CARTILAGE AND BONE IN THE KNEE IN VIVO

关节软骨是一种特殊的，坚硬但灵活的组织衬里骨关节内，如膝盖。该组织负责在身体活动期间沿沿着膝关节表面均匀分布巨大的机械负荷。预期膝关节软骨在许多年的生命中管理这些机械负荷而不遭受损伤。然而，机械负荷显然会导致软骨以及下面的骨结构破裂，导致关节炎。很少有研究探索这些力学在降解或保护人类膝盖中的关节软骨和底层骨骼方面的复杂性。本研究项目的目的是研究人类膝关节内关节软骨和底层骨对短期和长期机械载荷的反应。具体来说，我将1）量化和比较膝关节软骨变形后，高冲击负荷（跳跃），静态负荷（弓步）和重复负荷（重复单膝弯曲）。不同的序列和运动休息比将表征关节软骨对这些机械载荷的不同组合的反应。2）定义长期暴露于机械载荷对关节软骨和底层骨骼功能适应的影响。3）探索膝关节肌肉改变关节软骨对机械载荷反应的能力。在实验室中，先进的数码相机，结合最先进的测量力量和肌肉活动的系统，将分析不同类型负荷下的膝关节力学。磁共振成像，然后专门的图像分析将评估关节软骨和底层骨的短期和长期的机械负荷的反应。这项工作将是第一个证明机械负荷之间的剂量-反应关系，并确定肌肉在保护膝关节组织中的调节作用。这项工作对于改善加拿大人膝关节炎的检测、管理和治疗至关重要。

Articular cartilage is a specialized, stiff yet flexible tissue lining bones within joints, such as the knee. This tissue is responsible for evenly distributing the enormous mechanical loads along the knee joint surfaces during physical activities. Knee cartilage is expected to manage these mechanical loads over many years of life without suffering damage. However, mechanical loads can clearly cause the breakdown of cartilage, as well as the bony structure underneath, leading to arthritis. Little research has explored the complexities of these mechanics in degrading or protecting articular cartilage and the underlying bone in the human knee. The purpose of this research program is to study the responses of articular cartilage and the underlying bone to short-term and long-term mechanical loads within the human knee. Specifically, I will 1) Quantify and compare knee cartilage deformations after high impact loads (jumping), static loads (lunging) and repetitive loads (repeated single knee bends). Different sequences and exercise-to-rest ratios will characterize responses of articular cartilage to different combinations of these mechanical loads.2) Define the impact of long-term exposure to mechanical loads on functional adaptations of articular cartilage and underlying bone.3) Explore the ability of knee muscles to modify the responses of articular cartilage to mechanical loads.In the laboratory, sophisticated digital cameras, combined with state-of-the-art systems that measure forces and muscle activity, will analyze knee mechanics during different types of loads. Magnetic resonance imaging followed by dedicated image analyses will evaluate the responses of articular cartilage and the underlying bone to short-term and long-term mechanical loading. This work will be the first to demonstrate a dose-reponse relationship between mechanical loading and define the modulating role of muscle in protecting knee tissues. This work is fundamental to improving the detection, management and treatment of knee arthritis for Canadians.