title: Contact mechanics and elastohydrodynamic lubrication in a novel metal-on-metal hip implant with an aspherical bearing surface.
abstract: Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the radius of the curvature of a bearing surface and consequently improving the conformity between the head and the cup. In this study, a novel metal-on-metal hip implant employing a specific aspherical bearing surface, Alpharabola, as the acetabular surface was investigated for both contact mechanics and elastohydrodynamic lubrication under steady-state conditions. When compared with conventional spherical bearing surfaces, a more uniform pressure distribution and a thicker lubricant film thickness within the loaded conjunction were predicted for this novel Alpharabola hip implant. The effects of the geometric parameters of this novel acetabular surface on the pressure distribution and lubricant thickness were investigated. A significant increase in the predicted lubricant film thickness and a significant decrease in the dry contact and hydrodynamic pressures were found with appropriate combinations of these geometric parameters, compared with the spherical bearing surface.
authors.affiliation: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK. mnqm@leeds.ac.uk
authors.forename: Qingen
authors.initials: Q
authors.lastname: Meng
authors.forename: Leiming
authors.initials: L
authors.lastname: Gao
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Peiran
authors.initials: P
authors.lastname: Yang
authors.forename: John
authors.initials: J
authors.lastname: Fisher
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D055119:Elastic Modulus; D019544:Equipment Failure Analysis; D017276:Friction; D006622:Hip Prosthesis; D006801:Humans; D008153:Lubrication; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D011474:Prosthesis Design; D013499:Surface Properties
chemical_list: D008670:Metals