# Usability and acceptability of a power tool with electronic depth gauge for orthopedic drilling – a preclinical randomized controlled trial in sawbones

## TL;DR

This study tested a new electronic depth gauge for orthopedic drilling and found it to be faster and highly usable, though it did not reduce screw changes significantly.

## Contribution

The study introduces and evaluates an electronic depth gauge for orthopedic drilling in a preclinical trial, comparing it to traditional manual tools.

## Key findings

- The electronic depth gauge significantly reduced the time required to measure screw length, especially for medical students.
- The System Usability Scale (SUS) score was 87.5, indicating excellent usability of the electronic depth gauge.
- There was no significant difference in the rate of screw changes between the electronic and manual depth gauges.

## Abstract

Orthopedic drilling and screw placement require precision to obtain the effect of bicortical screwing and avoid complications such as soft tissue damage. Traditional manual depth gauges, while effective, are prone to human error. This study evaluates the usability and acceptability of an automated electronic depth gauge compared to a conventional manual depth gauge in a preclinical setting.

A randomized controlled cross-over trial was conducted with 45 participants of varying clinical experience (12 medical students, 11 resident doctors, and 22 consultants, 14/22 were senior consultants) at Aarhus University Hospital. According to randomization, participants used either the “electronic -> manual” or “manual -> electronic” depth gauge and subsequently the sequence “with -> without” or “without -> with” soft tissue protector to measure screw length in sawbones. Efficiency was assessed by measuring time (savings), and usability was evaluated using the System Usability Scale (SUS).

The electronic depth gauge significantly reduced the time required to measure screw length, with medical students saving the most time, p < 0.001. 65/331 (20%) of screws were changed, with no difference in the rate of screw changes between manual and electronic depth gauges, p = 0.76. Level of experience was significantly correlated with the rate of screw changes, p = 0.03. Resident doctors changed fewer screws than medical students, with no difference between the remaining groups. The median SUS score was 87.5, indicating excellent usability. Most participants rated the tool as “best imaginable” or “excellent.”

The electronic depth gauge was time-efficient and surgeons rated it as highly usable. However, screw exchanges were not significantly minimized in this study, which might be mitigated by proper training and awareness of device-specific recommendations. The effect of electronic depth gauges on screw exchange rates and its clinical applicability warrents further research.

The online version contains supplementary material available at 10.1007/s00402-025-05839-3.