An axisymmetric model of acetabular components in total hip arthroplasty.

An axisymmetric finite element model with nonaxisymmetric loading of an acetabular arthroplasty and the surrounding pelvic bone is presented. Model variations include ultra high density polyethylene acetabular components of varying wall thicknesses and metal backed ultra high density polyethylene components. Each of the two component types is modeled as implanted within an acetabulum with intact subchondral bone and within an acetabulum without subchondral bone. Thin wall polyethylene acetabular prostheses are predicted to increase, relative to thick wall components, maximum stresses in the cement-bone composite. Trabecular bone stresses are predicted to increase with the removal of subchondral bone. Stiffer metal-backed acetabular components are predicted to reduce maximum cement and bone stresses and to abridge the effects of altered component wall thickness and of subchondral bone removal.