Chapter 4 Dynamic Analysis of Human Knee S. Yoshida, U. Tiwari, A. Saladino, M. Nguyen, D. Hollander, B. Boudreaux, and B. Hadley Abstract Knee joint weakness and disorders are extremely common; with development of a new methodology for early detection of knee disorders in mind, various dynamics tests have been conducted. Subjects were requested to perform exercises of certain patterns including squats and marching at a constant rate for 70 (s). A force plate, acoustic sensor, and set of electromyographic (EMG) sensors were used to measure the ground reaction force and torque to the foot, the vibration from the knee cavity, and the electrical activity of muscles. The acquired signals were analyzed in the frequency domain to associate with certain biomechanical parameters. Preliminary studies indicated clear correlations between several features of the Fourier spectra and biomechanical parameters. The force and torque signals from a knee with a torn meniscus showed considerable broadening in the Fourier spectra around the peak of the exercise frequency (e.g. the 1 Hz peak of the torque associated with the knee extension from 1 Hz marching) and higher transfer function to other degrees of freedom, indicating instability of the injured knee. The acoustic sensor signal from an arthritic knee indicated significant attenuation due to the fluid in the knee cavity, leading to the extremely poorly defined spectral feature. The femoral efficiency, defined by the transfer function from the EMG signal to the force/torque of the dominant degree-of-freedom, showed clear correlation to fatigue in the amplitude and frequency. Keywords Knee dynamics • Knee disease detection • Electromyography 4.1 Introduction Knee disorders are very common. It is the second leading cause of physical disability behind ischemic heart disease in the US for persons over 50 [1]. The most prevailing diagnostic methods are X-ray and MRI (Magnetic Resonance Imaging). Although these assessments are well-developed techniques there are two issues. First, they visualize abnormality in the knee joint or surrounding tissues, not diagnose the functionality. Often the disorder is too advanced when the abnormality appears. During routine assessments, MRI images can appear normal but the patient feels intense pain or has a serious functional problem. Obviously there is a latent issue that does not show up in the MRI. Second, the diagnostic is static. The knee joint is one of the most complex joints in the human body. It is possible that an issue in other part of the knee kinetic chain could be contributing to the kinematic pathologies that lead to the pain pathologies. It is rather common that a lower back problem tightens pelvis, creating quadriceps femoris tightening and causes kinematic pathologies at the knee leading to patellar and joint related pain. Some empirical function tests are used for diagnosis but they are qualitative. Dynamic and quantitative diagnostic methods are beneficial not only for an early detection of knee injuries but also for more accurate and overall assessment of the issue. Considering the above situation, we started a research project [2]. In this project, our focus is dynamic analysis of knee motion based on physical interpretations. We use as many types of data as possible so that we can characterize the dynamics from various viewpoints. With practical applications in mind, we also make the measurement as simple as possible. Recently, we obtained several data sets that we believe verify the usefulness of the proposed methodology. The aim of this paper is to present the experiment and discuss the results of the analysis on the recent experiment. S. Yoshida (*) • U. Tiwari Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, LA 70402, USA e-mail: syoshida@selu.edu A. Saladino Department of Computer Science and Industrial Technology, Southeastern Louisiana University, Hammond, LA 70847, USA M. Nguyen • D. Hollander • B. Boudreaux • B. Hadley Department of Kinesiology and Health Studies, Southeastern Louisiana University, Hammond, LA 70845, USA #The Society for Experimental Mechanics, Inc. 2017 C.S. Korach et al. (eds.), Mechanics of Biological Systems and Materials, Volume 6, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-41351-8_4 25
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