Elastohydrodynamic lubrication and wear modelling of the knee joint replacements with surface topography

Abstract

This numerical study predicted wear of lubricated total knee replacements with the existing of textured surface and the possibility of surface designs to reduce wear. In the first part, a wear model of metal-on-polyethylene total knee replacement was developed. The medial and lateral knee compartments was accounted for separately, with the contact force and motion during walking cycles applied. An adapted Archard wear formula was employed where the wear factor was an exponential function of the 'Lambda ratio' (film thickness to the average roughness). Wear of the soft bearing surface (polyethylene insert) was simulated with regularly geometry update until a steady-state wear observed. In the second part, the effect of surface topography of the knee replacements was investigated. The surface texturing techniques have shown promising benefit to machine components in many areas of engineering practice. The texture parameters were designed using the Taguchi method for the geometry, size, and distribution of the micro dimples. It was observed that the lateral compartment may benefit from surface texturing if dimples were properly designed, while the texturing showed hardly advantageous effect on the medial surface in terms of lubrication enhancement and wear reduction. Some results were presented in the 6th World Tribology Conference.

Amorphous Carbon Coatings for Total Knee Replacements—Part II: Tribological Behavior

“…However, with advances in the simulation of the elastohydrodynamic lubrication (EHL) in THAs, some more sophisticated numerical models have also been developed for TKAs. The studies from Su et al [ 64 , 65 ] based upon a coupled solution of the hydrodynamics and the elastic deformation by a multigrid finite difference and constraint column model or Gao et al [ 66 ] using a multigrid and spherical fast Fourier transformation-based approach may be mentioned as examples. Lately, Marian et al [ 67 ] introduced an approach based upon full-system FEM combined with comparisons with experimental measurements from a knee simulator using optical fluorescence microscopy [ 68 ].…”

Design of Amorphous Carbon Coatings Using Gaussian Processes and Advanced Data Visualization

“…However, several experimental investigations focus on improving the tribological effectiveness of joint replacements [21][22][23] and lubrication conditions in prostheses [24][25][26], some experimental investigations are complemented with computer-aided or computational methods to improve the prediction and findings [27][28][29]. Nevertheless, the exact interactions of coating process parameters and resulting properties are mostly qualitative and only valid for certain coating plants and in certain parameter ranges.…”

Transient mixed lubrication model of the human knee implant

“…This is performed in order to minimise wear and improve implant performance, increasing the reliability of the implant, and is the focus of this work. Some efforts have been made to numerically model lubrication in the knee implant [17][18][19][20][21]. These models often simplify the geometry of the implant by considering an elliptical contact model [21][22][23], with well-documented numerical methods employed for a fast and efficient solution [24,25].…”

“…Some efforts have been made to numerically model lubrication in the knee implant [17–21]. These models often simplify the geometry of the implant by considering an elliptical contact model [21–23], with well‐documented numerical methods employed for a fast and efficient solution [24, 25]. These studies suggest that the geometry of the opposing surfaces determines the pressure distribution, highlighting the importance of accurately representing the geometry in lubrication modelling.…”