[Preoperative planning in hip endoprosthetics: presenting a computer-assisted system using CAD software].

The implantation of hip prostheses is a complex operation if one takes in consideration the peculiar features of the different types of implants, the knowledge and skill of the surgeon and the differing characteristics of the patients. In particular, biomechanical parameters have to be respected if a good long-term outcome is to be achieved. Normally the planning of the operation is done with colored pencils and tracing paper. In this paper we present a computer-based system for the planning of arthroplasty with which it is possible to obtain precise two-dimensional simulation of the operation after entering the bone contours, as visualized radiographically, into CAD software.