Bone remodelling around uncemented metallic and ceramic acetabular components

Stress shielding-induced bone resorption around cementless acetabular components has been indicated as a potential failure mechanism that may threaten long-term fixation. Using a bone remodelling algorithm in combination with three-dimensional finite element models of intact and implanted pelvises and musculoskeletal loading during normal walking, the objectives of the study were to investigate the deviations in load transfer due to implantation and bone adaptation around cementless metallic and ceramic acetabular components. Variations in implant-bone interfacial condition affected strain shielding and bone remodelling; strain shielding was higher for the bonded condition as compared to the debonded condition. For bonded interfacial condition, severe bone resorption, 20%-50% bone density reduction, was observed within the acetabulum. Considering debonded implant-bone interface, bone density increase of 50%-60% was observed around the supero-posterior part of acetabulum, whereas bone density reductions were low (2%-15%) in other locations. The implant-bone interface appeared less likely to fail, post-operatively and after bone remodelling. Moreover, the implant-bone micromotion was found to be low, less than 100 µm. Strain shielding and bone remodelling were almost similar for the metallic and ceramic components. Based on the results of this study, the ceramic acetabular component appeared to be a viable alternative to metal.