DETERMINING FRICTIONAL BEHAVIOR OF VITAMIN E BLENDED UHMWPE

摘要

Frictional behaviors of articulating surfaces have been recognized as critical factors affecting their service life because these behaviors play very important role on wear of ultrahigh molecular weight polyethylene (UHMWPE) which causes failure of artificial joint replacements. The objective of this study is to determine temperature rise as a function of sliding time and maximum load for the articulating surfaces of vitamin E blended UHMWPE acetabular component paired with a cobalt-chromium (CoCrMo) femoral component. Additionally frictional torque between the bearing surfaces was measured and friction coefficient was calculated. Frictional measurements of the joints were carried out on a custom made hip joint friction simulator. The prostheses were in 28 mm diameter. Applied static loads were changed from 200 N to 1500 N. In flexion-extension plane, a simple harmonic oscillatory motion between ±24° was applied to the UHMWPE acetabular component. The period of motion was 1 Hz and the tests were run up to 11000 cycles. Temperature rise in acetabular and femoral component is recorded with embedded thermocouples. Also the tests are repeated with UHMWPE acetabular component. The results are compared in terms of UHMWPE and vitamin E blended UHMWPE.