title: Effect of bearing geometry and structure support on transient elastohydrodynamic lubrication of metal-on-metal hip implants.
abstract: An effective lubrication can significantly reduce wear of metal-on-metal artificial hip joints. The improvement of the lubrication can be achieved through the optimisation of the bearing geometry in terms of a small clearance and/or the structural support such as a polyethylene backing underneath a metallic bearing in a sandwich acetabular cup form. The separate effects of these two factors on fluid film lubrication of 28 mm diameter metal-on-metal total hip joints under walking conditions were numerically investigated in this paper. The results show that a larger lubricant film due to the polyethylene backing can be significantly enhanced by the transient squeeze-film action, particularly during the stance phase, and a similar lubricant film can be developed for both the monolithic cup relying on the smaller clearance and the sandwich cup benefiting from the polyethylene backing. Both cup systems can function in a wide range of lubrication regimes, covering both mixed and fluid film, under the current design and manufacture conditions.
authors.affiliation: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK. menfl@leeds.ac.uk
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Jin
authors.forename: Paul
authors.initials: P
authors.lastname: Roberts
authors.forename: Peter
authors.initials: P
authors.lastname: Grigoris
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004548:Elasticity; D004867:Equipment Design / Q000379:methods*; D019544:Equipment Failure Analysis / Q000379:methods*; D017276:Friction; D006622:Hip Prosthesis; D008153:Lubrication; D008670:Metals / Q000737:chemistry*; D008962:Models, Theoretical; D014783:Viscosity
chemical_list: D008670:Metals