This paper describes FRACAS, a computer-integrated orthopaedic system for assisting surgeons in performing closed medullary nailing of long bone fractures. FRACAS'' goals are to reduce the surgeon's cumulative exposure to radiation and to reduce surgical complications associated with alignment and positioning errors of bone fragments, nail insertion, and distal screws locking. It replaces uncorrelated, static fluoroscopic images with a virtual reality display of three-dimensional bone models created from preoperative CT and tracked intraoperatively in real-time. Fluoroscopic images are used to register the bone models to the intraoperative situation and to verify that the registration is maintained. This paper describes the system concept, the software prototypes of preoperative modules (modeling, nail selection, visualization), the intraoperative modules (fluoroscopic image processing and tracking), and preliminary in-vitro experimental results to date. Our experiments suggest that the modeling, nail selection, and visualization modules yield adequate and that fluoroscopic image processing with sub-millimetric accuracy is practically feasible on clinical images.

Keywords: Computer-aided orthopaedic surgery, trauma, long bone fracture reduction, fluoroscopic image processing

Journal of Computer-Aided Surgery Vol 3(6), May 1999, pp 271-288.