Knee joint mechanics assessments

膝关节前交叉韧带（ACL）的完整性丧失也会改变关节稳定性和动力学，并导致骨关节炎（OA）的风险和发病率升高。 然而，关节结构内关节接触力学的直接非侵入性体内量化受到限制。因此，正常健康关节力学的特征以及导致病理状况的特征还没有很好地建立。总体研究目标是了解关节力学，关节健康状况，关节损伤和修复机制之间的关系，以及与韧带损伤和修复相关的退行性变化的发展。将检验三个主要假设：（H1）通过体内膝关节刚度测量和ACL松弛预测检测ACL完整性和关节组织状况的差异，（H2）使用整合的MRI和关节负荷技术将腕骨力-变形（FD）特征与蛋白聚糖（PG）浓度相关，以及（H3）异常动态关节稳定性与体内关节刚度的改变相关，软骨FD特征和PG浓度。 在各种膝关节屈曲和负载条件下，对4个体内组的膝关节松弛和软骨力-变形特征进行成像和定量：健康、先天性关节松弛、ACL缺陷伴早期退行性变化和ACL缺陷伴重度OA。使用新型关节松弛器械、MR成像、图像配准技术和建模，将开发关节和ACL松弛组织特征的标准范围。将使用创新的成像技术和加载装置评估体内软骨变形特征并将其与软骨成分（蛋白聚糖浓度）关联起来。将使用3D运动分析评估每组的关节动态稳定性，并将其与组织特征相关联。这项研究为联合表征工具包奠定了基础，并为临床治疗评估提供了独特而新颖的进展。

The loss of integrity of the anterior cruciate ligament (ACL) in the knee can also alter joint stability and dynamics and lead to higher risk and incidence of osteoarthritis (OA). However, direct non-invasive in-vivo quantification of joint contact mechanics within the joint structures has been limited. Consequently, characteristics of normal healthy joint mechanics, and those leading to pathological conditions are not well established. The overall research goals are to understand relations amongst joint mechanics, joint health status, joint injury and repair mechanisms, and the development of degenerative changes associated with ligament injury and repair. Three main hypotheses will be tested: (H1) Differences in ACL integrity and joint tissue condition are detected with in-vivo knee joint stiffness measures and ACL laxity predictions, (H2) Cartilage force-deformation (FD) characteristics are correlated to proteoglycan (PG) concentrations using integrated MRI and joint loading techniques, and (H3) Abnormal dynamic joint stability is correlated with alterations in vivo joint stiffness, cartilage FD characteristics and PG concentrations. Knee joint laxity, and cartilage force-deformation characteristics will be imaged and quantified for 4 in-vivo groups: healthy, congenital joint laxity, ACL deficient with early degenerative changes and ACL deficient with severe OA, under various knee flexion and loading conditions. Using novel joint laxity device, MR imaging, image registration techniques, and modeling, normative ranges for joint and ACL laxity tissue characteristics will be developed. In-vivo cartilage deformation characteristics will be evaluated and correlated with cartilage composition (proteoglycan concentration) using innovative imaging techniques and loading devices. Joint dynamic stability will be assessed for each group using 3D motion analysis, and correlated to tissue characteristics. This research develops the foundations for a joint characterization toolkit, and provides a unique and novel advance with potential impact for clinical treatment evaluations.