Research on Extraction Algorithm of Central Point in Femoral Backbone

Central points in femoral backbone are invisible, and these points provide clinicians with key anatomical marker points in surgical procedures to assist clinicians to complete TKA (Total Knee Arthroplasty) precisely and quickly. The femoral medullary cavity is located inside the femur, and for extraction of central points in femoral backbone can be extended to the extraction of the centers of the femoral medullary cavity. In this paper, we propose a method to automatically extract central points in femoral backbone based on the femoral medullary cavity contour fitting algorithm. First, the feature points of the edge contour of the femoral medullary cavity were extracted using an automatic edge contour feature point extraction algorithm. Then, the ellipse fitting algorithm was used to fit the ellipse to the edge contour of the femoral medullary cavity based on the extracted feature points, and finally, the center of the ellipse was extracted using the ellipse fitting equation, i.e., central point in femoral backbone, which provided an important anatomical landmark for clinical orthopedic medicine. Experimental results show the proposed method achieves those errors of central point extraction in femoral backbone under 0.6 mm.