It has been hypothesized a change in stress on the cartilage of a joint is a significant factor in the initiation and progression of post-traumatic osteoarthritis. Without a reliable method for measuring stress, this hypothesis has largely gone untested. In this study, a novel, repeatable, and reliable method for measuring stress on the surface of articular cartilage in articular joints is presented. Small Fiber Bragg Grating (FBG) sensors capable of measuring normal stress between contact surfaces in diarthrodial joints were developed and validated. The small size of these sensors (diameter of 125-300 μm and sensing length of 1 mm) allows them to be inserted into the joint space without the removal of biomechanically relevant structures. In-vitro stresses on the surface of the cartilage for both healthy and surgically damaged joints were measured after implantation of the FBG sensors using in vivo generated gait kinematic data and a 6-degrees of freedom parallel robot. Along with our capability to reproduce in vivo motions accurately and the improvements in fiber optic technology, this study describes the first direct measurement of stress in a joint using in vivo gait kinematics.

中文翻译：

---

使用光纤技术和体内步态运动学对关节软骨表面的应力测量。

据推测，关节软骨应力的变化是创伤后骨关节炎发生和发展的重要因素。由于没有可靠的压力测量方法，这一假设在很大程度上未经检验。在这项研究中，提出了一种新的、可重复的、可靠的方法来测量关节关节软骨表面的应力。开发并验证了能够测量手动关节接触面之间法向应力的小型光纤布拉格光栅 (FBG) 传感器。这些传感器的小尺寸（直径为 125-300 μm，传感长度为 1 mm）允许它们插入关节空间而无需移除生物力学相关结构。在植入 FBG 传感器后，使用体内生成的步态运动学数据和 6 自由度并联机器人测量了健康关节和手术损伤关节软骨表面的体外应力。随着我们准确再现体内运动的能力和光纤技术的改进，这项研究描述了使用体内步态运动学对关节应力的首次直接测量。