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dc.contributor.authorDorbala, Venkata Navaneetaen_US
dc.date.accessioned2014-03-14T20:45:14Z
dc.date.available2014-03-14T20:45:14Z
dc.date.issued2012-03-12en_US
dc.identifier.otheretd-09102012-213353en_US
dc.identifier.urihttp://hdl.handle.net/10919/35008
dc.description.abstractBackground: Epidemiological studies suggest an increased incidence of osteoarthritis among workers in occupations requiring squat-lifting such as in construction, mining and farming. Squat-lifting postures can induce heavy mechanical loads on the joint, causing the articulating surfaces to deform. This can result in changes of vibration characteristics of the joint surfaces. Differences in the vibration characteristics of normal and pathological joints have been established and used in the past for classifying severity of disease. The purpose of this study was to examine the influence of cumulative mechanical load on the vibration properties of the knee joint and to gain an understanding of how these properties may relate to an increase in cumulative load placed on the joint. Methods: In this study, cumulative load was measured as the resultant knee joint torque during squat lifting, while a piezoelectric accelerometer was used to capture vibration signals from points on the knee during flexion and extension. Twelve university students were recruited for a repeated measures study. Each participant attended one session where they had to perform a series of six squat-lifting tasks on a force platform. Motion capture equipment was used to obtain kinematic data. The cumulative 3-D moment on the joint was calculated using inverse dynamics. Results: A visual inspection of an ensemble average constructed for the frequency spectrum of all participants revealed that differences may exist in the 750 Hz - 2000 Hz bandwidth for vibrations coming from the patella during flexion. Further statistical analysis by a t-test and ANOVA showed a decrease in the RMS power of the signal captured in this bandwidth before and after mechanical load was induced by squat lifting. A linear regression analysis indicated a significant correlation between cumulative 3-D moment on the knee joint and the median frequency of vibration signals from the patella during flexion in the 1000 Hz - 2500 Hz range. Conclusions: Overall, the results of this study indicate the possibility of a relationship between mechanical exposure on the knee joint and its vibration properties during joint movement. Despite the small sample size, a declining trend was observed in the normalized RMS power of signals with increase in loading. However, the quantitative nature of this relationship is not clear and the current study points towards a non-linear relationship between joint exposure and knee vibrations. Future studies must investigate this possibility using direct measures of joint loading, cartilage deformation and their relation to joint vibrations.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartDorbala_N_T_2012.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectdynamic loadingen_US
dc.subjectMRIen_US
dc.subjectetiologyen_US
dc.subjectviscoelasticen_US
dc.subjectmechanomyographyen_US
dc.subjectensembleen_US
dc.subjectacousticen_US
dc.titleQuantification of Cumulative Load on the Knee using a Vibration Emission Methoden_US
dc.typeThesisen_US
dc.contributor.departmentIndustrial and Systems Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineIndustrial and Systems Engineeringen_US
dc.contributor.committeechairAgnew, Michael J.en_US
dc.contributor.committeememberNussbaum, Maury A.en_US
dc.contributor.committeememberMadigan, Michael L.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09102012-213353/en_US
dc.date.sdate2012-09-10en_US
dc.date.rdate2012-09-28
dc.date.adate2012-09-28en_US


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