Measurement of Intrameniscal Forces and Stresses by Two Different Miniature Transducers

Abstract

Injuries to the knee joint are common and often have an adverse impact on a patient's quality of life. It is therefore important to understand the load transfer mechanism of the knee, especially with regard to the loading of the menisci in different positions and under different conditions. To date, only contact pressure between joint surfaces and menisci, as well as circumferential strain, have been measured by pressure sensors and strain gauges. Therefore, the aim of this study was to investigate the spread of axial load within the menisci and the effect of the knee flexion angle on the axial load within the menisci. Intrameniscal forces were measured with Fiber Bragg Grating (FBG) sensors and conductive rubber sensors in porcine knee joint specimens. The changes in pressure were measured under different loading conditions. Measurement of the intrameniscal pressure is feasible. Although, there is some existence of variations in readings, some trends can be inferred. From the overall trend, it was observed that higher stress occurs at lateral central and lateral posterior regions. As the occurrences of injuries are mainly at the medial meniscus, this may imply that the level of stress is secondary to the mobility of the meniscus in incidents of injuries. It was found that the posterior meniscofemoral ligament plays a crucial role in the mechanics of the lateral meniscus.

Experimental Methods for Studying the Contact Mechanics of Joints

“…Similarly, fiber optic sensors change how they reflect ultraviolet light along their length when they undergo tensile or compressive strain [ 90 , 91 ]. They have been used at various interfaces to measure axial load at one location within a porcine knee meniscus [ 92 ], spine disc internal pressure [ 93 ], and bone-implant interface stress [ 94 ]. Their main strengths are small size, high precision, biocompatibility, no damage done to any electronic components even under high strain, and no interference from electromagnetic sources.…”

Joint Moment Responses to Different Modes of Augmented Visual Feedback of Joint Kinematics during Two-Legged Squat Training

“…Future studies could also address limitations in our protocol by using high-resolution force plates and more complete marker sets designed and calibrated for 3-D anatomical assessment of lower-extremity joint mechanics [79,80]. However, our simplified measures and analyses for joint moments were on par with similar studies for various applications [81][82][83] and, more importantly, were consistent with the visual feedback provided in this study, i.e., three-segment stick figure motions projected onto the sagittal plane. Furthermore, the measurement resolution of our methods did not prevent the identification of significant differences in computed joint moments based on visual feedback features, i.e., the study's primary goal.…”

From conventional sensors to fibre optic sensors for strain and force measurements in biomechanics applications: A review

“…FBG sensors were also used in the original study of Goh et al (2007) with the purpose of measuring the axial load within the menisci of porcine knee joints. A transverse load was applied and to relate it better with the measured axial load, the FBG sensor was placed between uneven layers of carbon-epoxy composites using a buckle configuration (Tjin et al, 2001a;Goh et al, 2007). Calibration was accomplished with a mechanical testing machine and suggested a wavelength/load linear relationship.…”