Osteoarthritis affects more than 27 million Americans and cost nearly $5700 per person annually. [1], [2] It commonly affects the knee joint and has been linked to work involving prolonged knee bending. [3], [4] In restricted vertical working heights such as low-seam coal mines and aircraft baggage compartments, workers are forced to assume stooped, kneeling, or squatting postures to perform work. In order to protect the knees in these postures, we must have an understanding of what the internal knee structures experience under these conditions. A finite element model is being developed to quantify the stresses and strains in the tissues in static kneeling postures. The accuracy of any finite element model is heavily dependent on the input parameters (i.e. forces and moments). Therefore, the objective of this work was to develop a 3-D computational model which may be used to determine the net forces and moments applied to the knee joint during static kneeling. The developed model uses inverse dynamics to determine the net forces, net moments, and joint angles for subjects while kneeling near full flexion, kneeling on one knee, kneeling near 90° flexion, and squatting. Motion data, ground reaction forces, and pressures between the thigh and calf and heel and gluteal muscles were inputs into this model. Additionally the thigh-calf contact force, which was shown to be significant [5], and the heel-gluteus contact force, which had not been previously investigated, were inputs in this model. Data from two subjects were analyzed with and without the subject wearing kneepads. Kneeling near full flexion and squatting created sagittal joint moments 3 to 5 times larger than standing in one subject. Moments of this magnitude may be significant to cause cartilage damage. It was also found that the moments caused by the thigh-calf and heel-gluteus contacts act to extend the knee, thereby reducing knee moments in fully flexed postures.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-09102008-170002 |
| Date | 28 January 2009 |
| Creators | Pollard, Jonisha Patrice |
| Contributors | Jean L. McCrory, PhD, Richard E. Debski, PhD, Rakie Cham, PhD, Mark S. Redfern, PhD |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-09102008-170002/ |
| Rights | unrestricted, I 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 University of Pittsburgh 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. |
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