Subject -specific FE model for the prediction of the relative micromotion in a total hip implant: verification and validation

The most common reason for the aseptic loosening of cementless hip stem is the lack of primary stability as the presence of an excessive relative micromotion at the boneimplant interface [1]. Despite pre-clinical validation has remarkably improved over the last few years, some important factors affecting implant biomechanics have still to be considered. Most of the previous numerical studies on hip arthroplasty were based on models of composite femurs. However, subject-specific factors (skeletal anatomy, mechanical properties, implant position) are needed to produce helpful outcomes for clinical practice. In addition, these models were developed using time consuming structured meshes frequently lacking of careful verification and validation phases. Aim of the present work is the development of a Finite Element (FE) model of an implanted femur taking into account the specificity of subject as well as the planned surgery technique parameters. Specific aims are the verification of the numerical accuracy of the FE model and the analysis of the predicted relative micromotions compared to experimental results (validation).