title: The biochemical characteristics of wear testing lubricants affect polyethylene wear in orthopaedic pin-on-disc testing.
abstract: Lubricant protein concentration is known to affect crosslinked polyethylene wear in in vitro testing; however, the biochemical nature of these lubricants may also have a significant effect on wear and dictate its clinical relevance. A modified approach to pin-on-disc testing was implemented to explore the effect of four biochemically different lubricants on the wear of two types of crosslinked polyethylene materials (XLK™ and Marathon™; DePuy Synthes, Warsaw, IN, USA). XLK was associated with higher wear rates than Marathon. In comparison to lubricants containing deionized water, lubricants containing phosphate buffered saline solution and hyaluronic acid increased osmolality by up to 1.2 times and thermal stability by up to 1.4 times. This biochemical change reduced wear by up to 12.5 times. Wear rates for XLK and Marathon differed by a factor of 3.2 using lubricants with phosphate buffered saline solution as the dilutive media, but only 2.0 for lubricants with deionized water. Interestingly, varying the concentration of hyaluronic acid did not have a significant effect on wear, and differences between XLK and Marathon wear rates were not found to be statistically significant when hyaluronic acid was added to the lubricant. The findings of this study showed that increasing the osmolality and thermal stability of lubricants to more clinical levels decreased wear; however, the effect of hyaluronic acid on wear may not be apparent in simplistic pin-on-disc testing. It was suggested that phosphate buffered saline solution be used as the dilutive media of choice in order to better differentiate the ranking of materials while maintaining some clinical relevance.
authors: Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada.
authors: Leah E
authors: LE
authors: Guenther
authors: Concordia Joint Replacement Group, Winnipeg, MB, Canada.
authors: Thomas R
authors: TR
authors: Turgeon
authors: Concordia Joint Replacement Group, Winnipeg, MB, Canada.
authors: Eric R
authors: ER
authors: Bohm
authors: Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada Concordia Joint Replacement Group, Winnipeg, MB, Canada brandtjm@gmx.net.
authors: Jan-M
authors: JM
authors: Brandt
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019544:Equipment Failure Analysis / Q000379:methods*; D017276:Friction; D007595:Joint Prosthesis; D054327:Lubricants / Q000737:chemistry*; D008422:Materials Testing; D020959:Polyethylene / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D054327:Lubricants; D020959:Polyethylene
keywords: Wear; lubricant; orthopaedic; pin-on-disc; polyethylene; tribology