Influence of the fixation region of a press-fit hip endoprosthesis on the stress-strain state of the “bone-implant” system

The FEM analysis has shown that for the diaphyseal fixation, the area of contact between the surface of the endoprosthesis and the bone is insufficient and leads to large stresses in the implant accompanied by stress concentration in the distal femur. An increase in the area of contact between the implant and the bone raises the stiffness of the "bone-implant" system, which, in turn, reduces stresses in the implant. The applied metaphyseal-type fixation yielded an improvement of results regarding behaviour of the femoral bone and the stem prosthesis. Namely, the study yielded the distribution of stress in the bone similar to the physiological stress state.