Long-term studies of cemented hip arthroplasty have shown that the most frequent cause of failure is the loss of mechanical fixation. Many factors as the bone quality, the implant design and the bone-implant interface are known to influence the quality of fixation of femoral components. Recent investigations have demonstrated that the risk of developing radiolucent lines at the bone-cement interface in the femur was more than 50 percent independently of the stem shape ^[33]. Evaluation of the bone-implant micromotion and interfacial stress is important for determining the mechanical environment acting on the bone cells ^[34]. This work is devoted to the developement of thermomechanical models and computational methods to investigate the initial fixation of orthopedic implants. Based on experimental and on clinical studies, ^[33], ^[27] we assume that radiolucencies at the bone-cement-stem interfaces could be attributed to high shear micromotions. Since the radiolucent line appears for most stem shape designs, a cemented femoral component was chosen to illustrate the developed models by varying different parameters ^[22]. From biology point of view, radiolucent lines at the bone-cement interface correspond to a fibrous layer, meaning that no close contact forms between the surrounding bone and the cement mantle. This gap is filled with fibroblasts which may be due to bone necrosis but also potentially by cell death by apoptosis ^[35] or demineralization ^[34]. Tissue change often appears after long durations but most probably ^[33]. Mechanical modelling of cement microcracking behaviour ^[19]