Hazard analysis of fracture-reduction robot and its application to safety design of fracture-reduction assisting robotic system

In this paper, we discuss the issue of safety in robot-assisted fracture reduction. We define the hazards of robot-assisted fracture reduction and design safety control methods. Although a large reduction force is required to reduce femoral neck fractures, an unexpectedly large force produced by a robot may cause injury to the patient. We have designed two mechanical failsafe units and a software force limiter; this along with velocity control can guarantee a safe operation in reduction force. In addition, to reduce the movement of bone fragments as much as possible, we devised spatially constrained control methods for fracture-reduction robots. The fracture-reduction system was evaluated using simulated fracture reductions.