Abstract
In orthopedic medicine, many operations are conducted to replace a bone with an implant. In the case of femoral stem fixation in total hip arthroplasty, the initial fixation is important. There are two concepts to consider for an ideal fixation: One common concept is that a wider contact area is better for fixation because lower stress must be better for biological tissues. Another concept is that the fixation force should be distributed to avoid the stress shielding of bone. Optimal design of joint prostheses has been generally investigated under these concepts. In this study, the 3-D FEM was used to map the stress distribution on the contact area of a virtual model of a bone tissue and prosthetic stems. The CT imaging of DICOM data was used to construct of a FF stem and an IMC stem models. Furthermore various mathematical model that simulating the contact mechanism between the materials and bone tissues were constructed. As a result, the wider the apparent contact area, the greater the fluctuation. The contact area can be limited by IMC stem fixation. It was concluded that the general concept unconditionally recommending a larger fixation site area for joint prostheses, should be revised.
