Design of a 3 axis wear testing device to evaluate the effect of slide to roll ratio on ultra high molecular weight polyethylene wear in total knee replacements

dc.contributor.authorLow, Benjaminen
dc.date.accessioned2008-09-07T22:04:38Z
dc.date.available2008-09-07T22:04:38Z
dc.date.issued2005en
dc.description.abstractMultidirectional motion occurs in total knee replacements (TKR), is a major factor in ultra high molecular weight polyethylene (UHMWPE) wear and is a requirement for wear tester and simulators. There are three ways the femoral component can move relative to the tibial component; sliding, rolling and gliding and these are defined by the slide to roll ratio. Previous wear tester research has investigated the effects of multidirectional motion and slide to roll ratio, individually but not combined. The project aim was to design a machine that combined multidirectional motion with variable slide to roll ratio. A three station wear testing machine was designed and built featuring flexion extension, variable anterior posterior translation, variable internal external rotation and a 2KN load per station. The TKR was simplified to a cylinder on flat. Lubrication was 25% bovine serum and each station had its own recirculation system. A million cycle validation test was successfully carried out on non-irradiated UHMWPE samples using a slide to roll ratio of 1 : 0.5 and the mean wear rate was 14.7mg/10^6 cycles. Polished areas and scratches from 3rd body abrasion were observed. Magnification revealed a fine ripple pattern with a 1-2 micron periodicity. Ripples were randomly oriented, perpendicular to the primary direction of motion and a small number were running parallel to the primary direction of motion, indicative of rolling motion. The results from the validation study show that the knee joint wear tester is capable of producing wear rates and wear mechanisms similar to those observed in other wear testers and knee joint simulators and has met the aim of the project.en
dc.identifier.urihttp://hdl.handle.net/10092/1105
dc.identifier.urihttp://dx.doi.org/10.26021/1343
dc.language.isoen
dc.publisherUniversity of Canterbury. Mechanical Engineeringen
dc.relation.isreferencedbyNZCUen
dc.rightsCopyright Benjamin Lowen
dc.rights.urihttps://canterbury.libguides.com/rights/thesesen
dc.subjectUHMWPEen
dc.subjectkneeen
dc.subjectTKRen
dc.subjectwear testen
dc.subjectslide to roll ratioen
dc.titleDesign of a 3 axis wear testing device to evaluate the effect of slide to roll ratio on ultra high molecular weight polyethylene wear in total knee replacementsen
dc.typeTheses / Dissertations
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorUniversity of Canterburyen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Engineeringen
uc.bibnumber1037644en
uc.collegeFaculty of Engineeringen
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