An In-vitro Investigation of Wear and Friction between a Bi-phasic Biomaterial and Articular Cartilage

BI-PHASIC BIOMATERIAL AND ARTICULAR CARTILAGE E.Northwood , R.Kowalski and J.Fisher * Institute of Medical and Biological Engineering, University of Leeds, Leeds, UK. +** DePuy CMW, Cornford Rd, Blackpool, England Email: [email protected] INTRODUCTION Natural articular cartilage has a unique biphasic lubrication regime [1]. Internal interstitial fluid pressure [2, 3] leads to low levels of friction under extended periods of loading, independent of any elastichydrodynamic surface lubrication effects. This intrinsic biphasic lubrication is the fundamental element within the lubrication of natural joints. The majority of total joint replacements are composed of single phasic metallic, ceramic or polymeric materials, which do not benefit from this intrinsic biphasic lubrication. While theoretically lower modulus single phasic materials can promote fluid film lubrication [4, 5] as a cushioned bearing, these essentially only produce low friction under periods of continuous motion and dynamic loading. However, for 95% of the time natural joints experience little or no motion. In contrast, biphasic hydrophilic polymers [6, 7] have shown reduced friction under adverse loading conditions. When considering hemi-arthroplasty or cartilage substitution solutions the biphasic properties of these material maybe important. The aim of this study was to compare the wear and friction properties of a biphasic material when ural articular cartilage under reciprocating motion. sliding against nat