A software simulation of tibial fracture reduction with external fixator

In modern orthopaedic practice, circular external fixators are frequently preferred to plaster cast for various reasons. The realignment of the two fractured bone segments is usually performed under a continuous fluoroscopy checking which involves a long radiation exposure time for both patients and surgeon. In order to overcome this problem, a computer controlled external fixator is under development. One relevant problem which this project faced in its initial stage was the difficulty to define in geometrical terms the manual reduction trajectory normally adopted by the surgeon. Basically it was a typical problem of empirical knowledge transfer from the surgeon to the engineer. Thus, it was necessary to create a common ground where the two experts could carry out the necessary analyses in order to define an empirical algorithm capable of suggesting a correction trajectory. The problem was solved by developing a simulation program called S.E.R.F. (Simulation Environment of a Robotic Fixator) provided with an extremely powerful graphic output, able to visualize the whole reduction trajectory from any viewpoint in space. The authors suggest the use of this kind of tool every time the techno-clinical information exchange is a critical issue.