Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Osteoarthritis Cartilage. 2010 Jul;18(7):909-16. doi: 10.1016/j.joca.2010.04.011. Epub 2010 Apr 29.
The purpose of this study was to investigate the in-vivo time-dependent contact behavior of tibiofemoral cartilage of human subjects during the first 300 s after applying a constant full body weight loading and determine whether there are differences in cartilage contact responses between the medial and lateral compartments.
Six healthy knees were investigated in this study. Each knee joint was subjected to full body weight loading and the in-vivo positions of the knee were captured by two orthogonal fluoroscopes during the first 300 s after applying the load. Three-dimensional models of the knee were created from MR images and used to reproduce the in-vivo knee positions recorded by the fluoroscopes. The time-dependent contact behavior of the cartilage was represented using the peak cartilage contact deformation and the cartilage contact area as functions of time under the constant full body weight.
Both medial and lateral compartments showed a rapid increase in contact deformation and contact area during the first 20s of loading. After 50s of loading, the peak contact deformation values were 10.5+/-0.8% (medial) and 12.6+/-3.4% (lateral), and the contact areas were 223.9+/-14.8 mm(2) (medial) and 123.0+/-22.8 mm(2) (lateral). Thereafter, the peak cartilage contact deformation and contact area remained relatively constant. The respective changing rates of cartilage contact deformation were 1.4+/-0.9%/s (medial) and 3.1+/-2.5%/s (lateral); and of contact areas were 40.6+/-20.8 mm(2)/s (medial) and 24.0+/-11.4 mm(2)/s (lateral), at the first second of loading. Beyond 50 s, both changing rates approached zero.
The peak cartilage contact deformation increased rapidly within the first 20s of loading and remained relatively constant after approximately 50 s of loading. The time-dependent response of cartilage contact behavior under constant full body weight loading was significantly different in the medial and lateral tibiofemoral compartments, with greater peak cartilage contact deformation on the lateral side and greater contact area on the medial side. These data can provide insight into normal in-vivo cartilage function and provide guidelines for the improvement of ex-vivo cartilage experiments and the validation of computational models that simulate human knee joint contact.
本研究旨在探讨人体在施加恒定全身体重负荷后的最初 300 秒内胫股关节软骨的时变接触行为，并确定内侧和外侧间室的软骨接触反应是否存在差异。
本研究共纳入 6 例健康膝关节。在施加负荷后的最初 300 秒内，通过两个正交的荧光镜捕捉每个膝关节的体内位置。从磁共振图像创建膝关节的三维模型，并用于再现荧光镜记录的体内膝关节位置。使用恒定全身体重下的峰值软骨接触变形和软骨接触面积作为时间的函数来表示软骨的时变接触行为。
在负荷的最初 20 秒内，内侧和外侧间室的接触变形和接触面积均迅速增加。在负荷 50 秒后，峰值接触变形值分别为 10.5+/-0.8%（内侧）和 12.6+/-3.4%（外侧），接触面积分别为 223.9+/-14.8mm(2)（内侧）和 123.0+/-22.8mm(2)（外侧）。此后，峰值软骨接触变形和接触面积保持相对稳定。软骨接触变形的相应变化率分别为 1.4+/-0.9%/s（内侧）和 3.1+/-2.5%/s（外侧）；接触面积的变化率分别为 40.6+/-20.8mm(2)/s（内侧）和 24.0+/-11.4mm(2)/s（外侧），在负荷的第一秒。超过 50 秒后，两个变化率均接近零。
在负荷的最初 20 秒内，峰值软骨接触变形迅速增加，在负荷约 50 秒后保持相对稳定。在恒定全身体重负荷下，软骨接触行为的时变响应在胫股关节的内侧和外侧间室之间存在显著差异，外侧的峰值软骨接触变形更大，内侧的接触面积更大。这些数据可以深入了解正常体内软骨功能，并为改进体外软骨实验和验证模拟人类膝关节接触的计算模型提供指导。
