Thermal Output of Oscillation Versus Forward Drilling of Bone

This study’s objective was to identify a difference in maximum temperature change during forward versus oscillating drilling of cadaveric bone. Paired femurs were dissected from the soft tissue of five cadavers. Each cadaver had one femur assigned to forward and the other to oscillation. The first drill hole was 2.5 cm distal to the lesser trochanter and the remaining 10 holes were evenly spaced 2 cm apart. A System 7 drill and 3.5 mm drill bit were attached to an Instron 5500R to provide a progressive force of 50 Newtons per minute for each drill hole. A thermal camera recorded each drilling. A new drill bit was used for each femur. Fifty bicortical drillings were analyzed in each group. The average time to complete forward drilling (45.0 seconds) was shorter compared to oscillation (55.5 s, p < 0.001). The average force required for forward drilling (27.7 N) was lower than for oscillation (44.3N, p < 0.001). The maximum change in temperature during the drilling process was similar (oscillating 100.2° F vs. forward 100.7° F, p = 0.871). The maximum change in temperature at the near cortex was lower for oscillation (78.1°F) compared to forward drilling (89.1°F, p = 0.011), while the maximum change at the far cortex was lower for forward drilling (89.3°F) compared to oscillation (95.8°F, p = 0.115) but not significantly. Overall, there is no difference in the thermal output between techniques. Oscillation may be beneficial in proximity to vital structures or to navigate narrow bony corridors, but it requires additional time and force. (Journal of Surgical Orthopaedic Advances 31(4):233–236, 2022) Key words: oscillation, thermal osteonecrosis, drilling