Artificial joint lubrication: Effect of Patient Synovial Fluid Properties on Implant Wear

Abstract

Introduction: Wear is essentially controlled by the properties of the lubricating film formed between the rubbing interface and the nature of the rubbing surfaces. Whilst our understanding of the mechanical and surface properties of metal artificial hips is good; we lack in knowledge on the synovial films which form during articulation and their implications on the performance of the artificial joint is a result of most current experimental research into prosthesis tribology being confined to the measurement of wear in joint simulators in pin-on-disc apparatus. Thus we understand very little about the nature of the lubricating film or the effect of joint kinematics formation. We also do not understand the effect of different synovial fluid (SF) chemistries on film formation, implant wear or failure. SF is an aqueous suspension of large and surface active molecules including proteins (albumin and γ-globulin), phospholids hyaluronan. The viscosity, protein content and pH level varies dependent of patient history. Trauma or d osteoarthritis and rheumatoid arthritis affect its chemical and physical properties. This can result in a significant change in the lubricating wear performance of SF. All in-vitro testing of metal-on-metal (MoM) serum (BS) as the fluid test medium with the addition of other chemicals to control the pH and bacterial growth. However composition standard is ill-defined, as the focus is to roughly match the overall protein content and effective viscosity of periprosthetic synovial fluid. The single composition does not capture the range of patient SF properties. Recently, the researchers presented a new mechanism for lubricating film formation in artificial hip joints These films did not obey classical fluid film theory; they are thicker than predicted in the currently accepted Newtonian fluid film m In this report we present coupled lubricant film thickness, and wear, measurements under carefully controlled speed and load conditions for different model SF composition. The effect of suspension concentration and chemical composition on lubrication performance is discussed, and the implications this may have for MoM hip function

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Cite this paper

@inproceedings{Myant2011ArtificialJL, title={Artificial joint lubrication: Effect of Patient Synovial Fluid Properties on Implant Wear}, author={C Myant}, year={2011} }