In vivo failure phenomena of ultra-high molecular weight polyethylene acetabular cups

摘要

During this study the distortion phenomenon was investigated on selected UHMWPE cups removed from patients, using 3dimensional measurement method. The cups investigated were machined by Metrimed Ltd. from ram extruded Chirulen 1020 type UHMWPE rods. The samples were measured with a 3D touch coordinate measurement device with an accuracy of 3 microns. It has been found that in an average use of 10 years the geometric change of the cups is about 0,5mm, and the distortion phenomenon of cups in males v.s. females were found to be different. The failure processes of the samples retrieved from males and females show different wear/creep behavior depending on gender, implicating that the differences in movement dynamics and anatomy have different effects on the distortion phenomena of the cups. Further studies are necessary on more specimens in order to give more detailed analysis.