title: Tribological evaluation of hydrogel articulations for joint arthroplasty applications.
abstract: Characterizing the wear behavior of hydrogel articulations is problematic and a standardized method has not yet been developed. The aims of this study were to evaluate the wear resistance of hydrogel-on-hydrogel articulations and to assess the suitability of a submerged measurement technique as a practical and non-destructive method in quantifying their wear rates. Five hydrogel bearings were tested for 5 million cycles using a pin-on-disk tester. As the test progressed, the coefficient of friction increased (Spearman's rho=0.76; p<0.001) while the surfaces of the pins were burnished (Spearman's rho=-0.31; p<0.001) and those of the disks got rougher (Spearman's rho=0.19; p<0.01). Environmental scanning electron microscopy analysis showed no evidence of gross wear and revealed similar surface morphology between contacting and non-contacting regions of specimens. These results support the finding of low wear, which were -1.4±8.3 and 6.6±35.3mm(3)/MC based on submerged and wet weights, respectively. Pins displayed higher wear than disks based on submerged weights. This was anticipated since surfaces of pins were constantly under load and cross-shear while only a portion of the disk in contact with the pin was loaded at a given time. Wet weights, on the other hand, indicated higher wear for disks than pins. In addition, submerged weights yielded a lower standard error of the mean in wear rates than wet weights, 3.7 and 14.6mm(3)/MC, respectively. These results indicated that submerged weights were more suitable than wet weights in quantifying wear of hydrogels in spite of unwanted effects of swelling.
authors.affiliation: School of Biomedical Engineering, Drexel University, USA. db434@drexel.edu
authors.forename: D
authors.initials: D
authors.lastname: Baykal
authors.forename: J S
authors.initials: JS
authors.lastname: Day
authors.forename: D J
authors.initials: DJ
authors.lastname: Jaekel
authors.forename: J
authors.initials: J
authors.lastname: Katta
authors.forename: K
authors.initials: K
authors.lastname: Mansmann
authors.forename: S M
authors.initials: SM
authors.lastname: Kurtz
mesh_terms: D001178:Arthroplasty; D001672:Biocompatible Materials; D017276:Friction; D020100:Hydrogels; D007596:Joints / Q000601:surgery*; D008422:Materials Testing; D019736:Prostheses and Implants; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels