Stress Measurements on the Articular Cartilage Surface Using Fiber Optic Technology and In-Vivo Gait Kinematics

• Published in: Annals of biomedical engineering Vol. 48; no. 12; pp. 2836 - 2845
• Main Authors: Vakiel, Paris, Shekarforoush, Mehdi, Dennison, Christopher R., Scott, Michael, Frank, Cyril B., Hart, David A., Shrive, Nigel G.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-12-2020; Springer Nature B.V
• Subjects: Biochemistry; Biological and Medical Physics; Biomechanics; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedical materials; Biomedicine; Biophysics; Bragg gratings; Cartilage; Cartilage (articular); Cartilage diseases; Classical Mechanics; Contact stresses; Diameters; Fiber optics; Gait; In vivo methods and tests; Kinematics; Measurement methods; Optical fibers; Original Article; Osteoarthritis; Parallel degrees of freedom; Robotic surgery; Sensors; Surgical implants
• ISSN: 0090-6964; 1573-9686
• DOI: 10.1007/s10439-020-02516-x

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
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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.