Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
J Biomech. 2010 Mar 22;43(5):849-57. doi: 10.1016/j.jbiomech.2009.11.018. Epub 2009 Dec 8.
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.
金属对金属髋关节植入物和结构支撑的承载面的直径和直径间隙已被认为是降低干接触和流体动压力并改善润滑性能的关键因素。另一方面，通过改变承载面的曲率半径，非球面承载面的应用也可以显著影响接触力学和润滑性能，从而提高头和杯之间的一致性。在这项研究中，采用了一种特殊的非球面承载面，即 Alpharabola，作为髋臼表面的新型金属对金属髋关节植入物，在稳态条件下对其进行了接触力学和弹流润滑研究。与传统的球面承载面相比，对于这种新型 Alpharabola 髋关节植入物，预测到在承载区域内具有更均匀的压力分布和更厚的润滑剂膜厚度。研究了这种新型髋臼表面的几何参数对压力分布和润滑剂厚度的影响。与球面承载面相比，这些几何参数的适当组合可以显著增加预测的润滑剂膜厚度，并显著降低干接触和流体动压力。
