The Effect of Insertion Technique on Temperatures for Standard and Self-Drilling External Fixation Pins

No studies have assessed the effects of parameters associated with insertion temperature in modern self-drilling external fixation pins. The current study assessed how varying the presence of irrigation, insertion speed, and force impacted the insertion temperatures of 2 types of standard and self-drilling external fixation half pins.

Seventy tests were conducted with 10 trials for 4 conditions on self-drilling pins, and 3 conditions for standard pins. Each test used a thermocouple inside the pin to measure temperature rise during insertion.

Adding irrigation to the standard pin insertion significantly lowered the maximum temperature (P <0.001). Lowering the applied force for the standard pin did not have a significant change in temperature rise. Applying irrigation during the self-drilling pin tests dropped average rise in temperature from 151.3 ± 21.6°C to 124.1 ± 15.3°C (P = 0.005). When the self-drilling pin insertion was decreased considerably from 360 to 60 rpm, the temperature decreased significantly from 151.3 ± 21.6°C to 109.6 ± 14.0°C (P <0.001). When the force applied increased significantly, the corresponding self-drilling pin temperature increase was not significant.

The standard pin had lower peak temperatures than the self-drilling pin for all conditions. Moreover, slowing down the insertion speed and adding irrigation helped mitigate the temperature increase of both pin types during insertion.