Towards Digital Template for Artificial Hip Implants Selection

Abstract

Technology of so-called “digital templating” is based on 3D parametric models of femur and endoprosthesis of hip. It is aimed in pre-operative planning, primarily for artificial hip implants selection, as well as visualization tool for other surgical activities planning. Parametric master model of a femur is developed from a series of 2D and 3D images obtained by different scanning methods, which include both X-ray based and optical. In that course, for the initial model we use optically scanned 3D images of cadaveric bones and their educational replica. Generated clouds of points are optimized during reconstruction process to ensure proper polygonization and creation of surface and solid models. Parametric definition of a femur uses a set of cross sectional parameters that provide anatomically consistent individualization (customization) of the master model. Family tables for different designs of endoprosthesis are also developed. The process of artificial hip implants selection assumes automatic positioning of a stem into femoral channel during which developed control mechanism calculates both the overlapping volume and the clearance between cortical bone and the stem. Depending on individual characteristics of a patient and orthopedic surgeon preferences the system ranks the alternatives and visualizes the correspondent data and solutions.