Drill Bone with Both Hands: Plunge Depth and Accuracy with 4 Bracing Positions.

Bone drilling is a critical skill honed during orthopaedic surgical education. How a bone drill is held and operated (bracing position) may influence drilling performance. Methods: A prospective study with randomized crossover was conducted to assess the effect of 4 bracing positions on orthopaedic surgical trainee performance in a simulated bone drilling task. Linear mixed effects models considering participant training level, preferred bracing position, height, weight, and drill hole number were used to estimate pairwise and overall comparisons of the effect of each bracing position on 2 primary outcomes of drilling depth and accuracy. Results: A total of 42 trainees were screened and 19 were randomized and completed the study. Drill plunge depth with a 1-handed drilling position was significantly greater by pairwise comparison to any of the 3 double handed positions tested: a soft tissue protection sleeve in the other hand (0.41 mm, 95% confidence interval [CI] 0.80-0.03, p = 0.031), a 2-handed position with the contralateral small finger on bone and the thumb on the drill (0.42 mm, 95% CI 0.06-0.79, p = 0.018), and a 2-handed position with the contralateral elbow braced against the table (0.40 mm, 95% CI 0.02-0.78, p = 0.038). No position afforded a significant accuracy advantage (p = 0.227). Interactions of participant height with plunge depth and accuracy as well between drill hole number and plunge depth were observed. Conclusion: Orthopaedic surgical educators should discourage trainees from operating a bone drill using only 1 hand to reduce the risk of iatrogenic injury due to drill plunging. Level of Evidence: Therapeutic Level II.