Orthopaedic Research Lab, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Robotics and Mechatronics Group, The Faculty of Electrical Engineering Mathematics and Computer Science, Technical Medical Centre, University of Twente, Enschede, the Netherlands.
Orthopaedic Research Lab, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Radiology, Stanford University, Stanford, CA, USA.
J Mech Behav Biomed Mater. 2019 May;93:43-51. doi: 10.1016/j.jmbbm.2019.01.022. Epub 2019 Feb 7.
Characterization of the main tibiofemoral ligaments is an essential step in developing patient-specific computational models of the knee joint for personalized surgery pre-planning. Tensile tests are commonly performed in-vitro to characterize the mechanical stiffness and rupture force of the knee ligaments which makes the technique unsuitable for in-vivo application. The time required for the limited noninvasive approaches for properties estimation based on knee laxity remained the main obstacle in clinical implementation. Magnetic resonance imaging (MRI) technique can be a platform to noninvasively assess the knee ligaments. In this study the aim was to explore the potential role of quantitative MRI and dimensional properties, in characterizing the mechanical properties of the main tibiofemoral ligaments. After MR scanning of six cadaveric legs, all 24 main tibiofemoral bone-ligaments-bone specimens were tested in vitro. During the tensile test cross sectional area of the specimens was captured using ultrasound and force-displacement curve was extracted. Digital image correlation technique was implemented to check the strain behavior of the specimen and rupture region and to assure the fixation of ligament bony block during the test. The volume of the specimen was measured using manual segmentation data, and quantitative MR parameters as T, T, and T were calculated. Linear mixed statistical models for repeated measures were used to examine the association of MRI parameters and dimensional measurements with the mechanical properties (stiffness and rupture force). The results shows that while the mechanical properties were mostly correlated to the volume, inclusion of the MR parameters increased the correlation strength for stiffness (R ≈ 0.48) and partial rupture force (R = 0.53). Inclusion of ligament type in the statistical analysis enhanced the correlation of mechanical properties with MR parameters and volume as for stiffness (R = 0.60) and partial rupture (R = 0.57). In conclusion, this study revealed the potentials in using quantitative MR parameters, T, T and T, combined with specimen volume to estimate the essential mechanical properties of all main tibiofemoral ligaments required for subject-specific computational modeling of human knee joint.
主要的胫股韧带的特征描述是为膝关节进行个性化手术规划开发特定于患者的计算模型的重要步骤。为了对膝关节韧带的机械刚度和断裂力进行特征描述，通常在体外进行拉伸测试，这使得该技术不适合体内应用。基于膝关节松弛度的有限的非侵入性方法来进行特性估计所需的时间仍然是临床实施的主要障碍。磁共振成像（MRI）技术可以作为一种非侵入性评估膝关节的平台。在这项研究中，目的是探索定量 MRI 和尺寸特性在特征描述主要胫股韧带的机械特性中的潜在作用。在对 6 条尸体腿进行 MRI 扫描后，对所有 24 个主要的胫股骨-韧带-骨标本进行了体外测试。在拉伸试验过程中，使用超声技术对标本的横截面积进行了捕捉，并提取了力-位移曲线。实施数字图像相关技术以检查标本的应变行为和断裂区域，并确保在测试过程中韧带骨块的固定。使用手动分割数据测量标本的体积，并计算定量 MRI 参数 T1、T2 和 T2*。使用重复测量的线性混合统计模型来检查 MRI 参数和尺寸测量与机械性能（刚度和断裂力）之间的关联。结果表明，虽然机械性能主要与体积相关，但包括 MRI 参数可以增加刚度（R≈0.48）和部分断裂力（R=0.53）的相关性。在统计分析中纳入韧带类型可以增强机械性能与 MRI 参数和体积之间的相关性，如刚度（R=0.60）和部分断裂（R=0.57）。总之，这项研究揭示了使用定量 MRI 参数 T1、T2 和 T2*以及标本体积来估计特定于个体的人类膝关节计算模型所需的所有主要胫股韧带的基本机械性能的潜力。
