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Title Contact pressure distribution of osteochondral defects of the knee [electronic resource] : effects of non-vertical walls / by Scott Ensminger.
Publication Info. 2012.

Location Call No. Status Notes
 Libraries Electronic Books  Electronic Resource - WSU ETD    AVAIL. ONLINE
Note Thesis supervisor: King-Hay Yang
Thesis Thesis (M.S.)--Wayne State University, 2012.
Summary Purpose: To examine the relationship between well-shouldered osteochondral defects and defects of different geometries by studying their effects on rim stress concentration and load redistribution in the human knee. Methods: Ten fresh-frozen cadaveric knees were mounted at 30° of flexion in a materials testing machine. Digital electronic pressure sensors were placed in the medial and lateral compartments of the knee. Dynamic pressure readings were recorded throughout the loading and holding phases as each knee was loaded to 700N and held for 5 seconds. Artificial defects were created in each knee to simulate well-shouldered defects and beveled-defects. Loading was repeated for well-shouldered and beveled osteochondral defects sized 6, 8, 10, 12, 14, 16, 18 and 20 mm. Results: Stress concentrations around rims of defects were shown to act similarly to a previous study by Guettler et al. As defect size increased, a rim of peak pressures formed on the adjacent cartilage with distance from defect center to rim of peak pressures increasing as defect size increased (p<0.05). Average radius from the center to the rim of peak pressure was found to be higher among beveled defects although this was not found to be statistically significant. Peak pressure values did not increase significantly as defects were enlarged. Conclusions: Beveled defects were found to affect rim stress concentrations over their well-shouldered counterparts. Although this result was not statistically significant, multiple studies point to a link between osteochondral defects and degeneration of surrounding articular cartilage. Based on this finding, it would be prudent when using a size criterion in assessing severity of an osteochondral defect, to use the outermost border of the defect as a measure of defect size.
System Details Mode of access: World Wide Web.
System requirements: Adobe Reader.
Added Author King-Hay Yang, advisor.
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