Textured surfaces for orthopedic implants.

摘要

Orthopedic implants have brought great benefit to human life; however the implants have a limited life time, with the main failure mode being wear. The purpose of this study was to reduce wear by improving the lubrication condition for the implants. This study developed a surface engineering approach for texturing orthopedic implants, with primary emphasis on the hip. The textured surface was prepared by applying a pattern of micro-dimples to the surface. Combined with human walking biomechanics, the textured surfaces had the benefits of encouraging lubricant entrainment under high load and restricting lubricant escape from the surfaces under low load.;Laser surface texturing (LST) was used to produce the dimples. A mathematical model was developed to relate laser operation parameters to the dimple geometric features. Precise dimple profiles could be achieved using such a model.;The finite element method (FEM) was used to describe the deformation of the textured surfaces. Design of experiments (DOE) was used to analyze the FEM results and to evaluate the lubricant generating ability of the textured surfaces. The results were analyzed for implants of different materials. The textured surfaces were the most effective for alumina-cup implants, with an over 300% increase of lubricant film thickness. The implant and the dimple geometric features were optimized in order to maximize the lubricant film thickness. Within the range of this study, large diametral clearance and small ball diameter of the implants as well as large diameter and depth of the dimple were in favor of increasing film thickness of the lubricant.