NUMERICAL-ANALYSIS OF ELASTOHYDRODYNAMIC SQUEEZE FILM LUBRICATION OF TOTAL HIP PROSTHESES

We have calculated the thickness of a fluid film between the acetabular cup and the femoral head of a total hip prosthesis using a mechanical analysis. A standard system geometry, standard values of material properties and standard biological conditions representative of a prosthesis currently in clinical use were selected. We used elastohydrodynamic lubrication theory and the theory of three-dimensional elasticity for the numerical analysis. With regard to this particular system we have shown that a minimum film thickness of slightly less than 2 μm and 0.30 μm exist during normal walking motion, for values of viscosity based on (i) synovial fluid from osteoarthritic joints and (ii) blood plasma respectively. We have concluded that the fluid film lubrication is possible in hip joint prostheses with sufficient quality of surface finish. © 1990.