A Mutlti-Scale FE Modeling Approach to Investigate the Contact Mechanics and Interfacial Stress of a Low Stiffness Porous Metal-Backed Acetabular Cup Available to Purchase

In modern Total Hip Arthroplasty (THA), modular metal-backed acetabular cups consisting of a metal shell backing with porous coatings for fixation and a modular polyethylene liner for articulation are currently the most widely used cementless acetabular cups. Modular acetabular cups give surgeons the flexibility to change femoral head size, liner offset, and liner-lip buildup during hip arthroplasty as well as the ability to change the liner without removing a bone-ingrowth metal shell during revision surgery. However, concerns have been noted with modular metal backed acetabular cups. Poor locking mechanisms have been blamed for backside wear and polyethylene liner dislodgement as well as debris which may lead to osteolysis [1]. In addition, the study of the load transfer around acetabular cups has shown that a stiff metal backing generates high stress peaks around the acetabular rim while it reduces the stresses transferred at the central part of acetabulum potentially causing stress shielding at the dome of acetabulum [2].