Effects of ingrowth, geometry, and material on stress transfer under porous‐coated hip surface replacements

Abstract
Three different interface geometries for porous ingrowth surface replacements of the hip were examined using two-dimensional linear and non-linear contact finite element analyses. The results indicate that incorporation of a nearly flat prosthesis interface between the surface replacement and the underlying cancellous bone may reduce stress shielding and improve stress transfer from the component. For all designs analyzed, the bone stress shielding was insensitive to component material stiffness when the elastic modulus was >30 MPa. The use of titanium instead of cobalt-chrome (Co–Cr) as the prosthesis material therefore had a negligible effect on stress shielding.