抄録
In total hip replacement, the fitting of the femoral stem, which is a component of the hip joint implants, to the femoral canal is important for stability of the stem. A surgeon determines the parameters such as the size, position and orientation of the stem based on a visual assessment of the relationship between the stem and femoral canal surface. However, visual assessment depends on a surgeon's subjectivity. Our work focuses on the development of an automated method for determining placement of the stem in the femoral canal, which is intended to emulate the expertise of an experienced surgeon. The proposed method is based on stem fitness, which is the measure of shape difference between the stem and femoral canal surface. The combinations of the size, position and orientation of the femoral stem, which provide the local maxima for stem fitness, are determined by exhaustive searching. We applied the automated method developed to four cases of patient data sets, and compared the results obtained from the automated method with those of an experienced surgeon. The results obtained were generally close to those of the experienced surgeon, and the difference from the experienced surgeon was 1.6mm and 1.3 degrees in the best case. These results suggest the feasibility of using the proposed method in clinical practice.
