Three-dimensional fracture simulation for preoperative planning and education

Background: Mental translation of the fracture pattern seen on two-dimensional (2-D) radiographs into the real three-dimensional (3-D), intraoperative situation may be difficult. In this study, a concept and a software for 3-D fracture simulation on a personal computer (PC) are presented enabling the surgeon to draw the fracture shown on plain radiographs onto a 3-D model of similar bone and to do virtual reduction and fixation. Material and Methods: A 2-D/3-D database of helical CT volume data from cadaveric tibiae with the corresponding 2-D radiographs was built. A new procedure was used to select bone being most similar to the patient's bone from the database. Tools for drawing the fracture on the 3-D bone model and for individual manipulation of 3-D objects - fragments and/or implants - were developed. Results: After having found the most similar bone in the database, a three-stage fracture simulation can be performed: fracture generation, fragment separation, and fragment manipulation. Each piece of the fractured bone can be individually translated or rotated around a specific point or axis in 3-D space. The corresponding simulated X-ray projection images can be generated from any perspective according to the fragment position and compared with the original radiographs. Simulation of internal fixation is also possible, including implant models. Conclusions: 3-D representation of a fracture may be helpful in understanding fracture morphology as well as reduction mechanisms even in cases where 3-D imaging would normally not be performed. The presented concept can be used for preoperative planning and for educational purposes. The presented software runs on a low-cost PC and may therefore support the surgeon's daily work in the near future.