BRIGE: Patterned Microtexture to Create Fluid Film Lubrication at Low Sliding Velocities in Prosthetic Knee Joints

University Of Utah, Salt Lake City UT

Investigators

Abstract

This Broadening Participation Research Initiation Grant in Engineering (BRIGE) grant provides funding for the design of prosthetic knee implant bearing surfaces with a patterned microtexture. The primary goal of this research is to extend implant durability compared to state-of-the-art smooth implants by creating hydrodynamic lubrication at low joint sliding velocities to reduce friction and wear. A model of the sliding components of a prosthetic knee joint with patterned microtexture will be implemented using a finite difference formulation. The defining parameters of the microtexture will be optimized to maximize the bearing load carrying capacity and the separation between the bearing surfaces. The model will account for the non-Newtonian nature of the lubricant (synovial fluid) and the variable spacing between the bearing surfaces during gait. Laser surface texturing will be used to fabricate the patterned microtexture. A prototype prosthetic knee implant with an optimized, patterned microtexture design will be built to validate the model and experimentally compare friction and wear of microtextured and smooth prosthetic knee bearing surfaces. This study will provide critical insight on the effect of microtexture for the transition from boundary lubrication to hydrodynamic lubrication at low, variable sliding velocities in the presence of a non-Newtonian lubricant. Specifically, the results of this research will contribute to improving the durability of bearing surfaces of prosthetic knee implants by drastically reducing friction and wear. This could mark the beginning of a new generation of prosthetic implants with much improved durability, to serve an aging population and reduce health care costs. By extension, this research will also apply to reducing friction and wear in other implants, such as hip and shoulder implants. During this project, participation of students from underrepresented groups will be promoted through K-12 outreach and undergraduate research. An interactive module and curriculum related to friction will be contributed to the annual Hi-GEAR camp at the University of Utah for female high school students. Additionally, a demo-kit will be part of the Discover Engineering Display, which visits high schools in the Salt Lake City metro area.