Design of a haptic simulator for osteosynthesis screw insertion

Osteosynthesis procedures require the insertion of self-tapping orthopaedic screws through bone plates and into one or two layers of cortical bone, in order stabilize the fractured bones. Applying too much torque can cause the screw to strip and lose purchase, reducing the effective hold of the screw against the plate. Experienced surgeons have developed a ¿feel¿ for the torque-rotation relationship that reduces the risk of stripping. A haptic simulator for orthopaedic screw insertion procedures is desirable for training surgeons to learn this relationship in a virtual reality practice scenario. A one-degree-of-freedom friction-based haptic device was designed and used to present bone screw insertion scenarios to expert surgeon users. Evaluation of the system indicated that realism may be improved through vertical motion of the virtual screw, and device calibration based on measurements in human bone.