Finite and boundary element method contact mechanics on rough, artificial hip joints

An extremely small roughness of constant height magnitude is considered on the femoral head of an artificial hip joint in order to determine the consequences of various regular shapes and clearances on the mechanical performance of this hip prosthesis via a properly coupled finite and boundary element method. In addition, different material combinations typical for widely used hard-on-hard and hard-on-soft hip joint replacements are also taken into account. By analysing the calculated pressure distribution and contact area between the femoral head and the acetabular cup in frictionless dry contact irrespective of material pairings in hip joints, it is shown that both the wavelength of roughness and the clearance significantly affect these mechanical quantities and accordingly too loose or too tight hip implants have to be avoided. Finally, in terms of all numerical findings a suitable optimal design of hip implants is also discussed.