Enhancement of Kirschner Wire for Bone Drilling

This study advances design and manufacturing of the tip geometry of the Kirschner wire (K-wire) — a popular orthopedic drilling tool with a sharp, three-sided trocar point — for improved bone drilling efficiency. Since there is no active cutting edge as there is for twist drill bits, bone drilling forces can be so large as to cause excessive heat generation and tool wear. Our modified K-wire consists of three slots at the tip to enhance cutting and chip (bone debris) evacuation. A finite element model was developed to simulate bone debris generation, thus predicting the improvement by the slot design. An experimental study was conducted to validate the model and ascertain actual drilling performance. During 5 mm drilling the maximum thrust force and torque were both reduced on average by 30–40% based on the experimental data. The overall trends of both force and torque agree with the model-predicted results.