Quantitative analysis of force and torque in bone drilling

Bone drilling is an important and the most frequent operation in orthopaedics and other bone surgical procedures. Prediction and control of drilling force and torque are critical to safe and efficient surgeries. This paper studies the drilling force and torque arising from bone drilling process. Drilling parameters such as drilling speed, feed rate, drill size and drill condition (sharp and worn) were changed to measure the force and torque in the direction of the drill penetration. Experimental results demonstrated lower drilling force using a sharp drill compared to a worn drill for similar drilling conditions. Contrary to the drilling force, lower torque was measured using a worn drill compared to a sharp drill. The drilling force was found to decrease with increase in drill speed and increased with rise in the feed rate using both types of drills. A linear drop in drilling torque was measured with increase in drilling speed. This study provided scientific information to orthopaedic surgeons and technicians to use appropriate surgical drill and cutting parameters to avoid overstressing of the bone tissue and drill breakage during drilling operations.