Effects of Retroversion and Anteversion Alignment in Cemented Hip Arthrosplasty

Cemented Hip Arthroplasty is one of the alternatives to replace hip joint for later stage of osteoarthritis. Prosthesis stem anteversion and retroversion are two type of mal-alignments that potential to occur in hip arthroplasty. In this study, a computational analysis of cemented hip arthroplasty was conducted to estimate effects of mal-alignment stem to the bone adaptation. 3D femoral bone was developed from computed topography (CT based) data of 54 years old male patients with body weight of 800N. Bone cement was modelled as polymethylmethacrylate (PMMA) (E= 2 GPa, v=0.3) and prosthesis stem model (E=200 GPa, v=0.28) was used as the prosthesis stem. Walking and stair climbing activities were considered in the analysis. The results were discussed on the resulting von Mises stress at femur, stem prosthesis, and cement mantle. Both anteversion and retroversion mal-alignments had increased the von mises stress in the femoral bone with retroversion indicated the highest stress magnitude. The higher stress in stair climbing activity may have contributed by higher loading magnitude and bending effects from the prosthesis stem.