Stripping Torque Model for Bone Screws

Abstract Correct torquing of bone screws is critical for positive patient outcomes in orthopaedic surgery. Under-or over-tightening can lead to thread stripping or screw loosening, leading implant/fixation failure and potential tissue damage disability. It has been proposed that an automated torque-limiting smart-screwdriver may be able use model-based methods determine the properties as are inserted, then these optimal tightening torque provide a torque-indication or-limitation enforce this limit. Previous work focused on identifying material from sensor data, but paper will address unanswered question torque-limit prediction. Here we have developed simple model stripping. This based assumption overtightening shear cylindrical section underlying material. augmented with stress concentration factor dependant geometry. was tested against experimental stripping-torque data. We found without stress-concentration produced predicted torques strong linear relationship values (R2 = 0.98), however magnitude predictions 2-3 times too high. Including brought into range values, before disrupted 0.80). Overall, approach promising prediction, needs more thorough testing materials screws, room improvement factor.