# The lesser trochanter profile is an accurate and reliable measure of femoral rotation for intramedullary nailing

## TL;DR

This study shows that the lesser trochanter profile is a reliable and accurate method for measuring femoral rotation during surgery, with consistent results across different skill levels.

## Contribution

The study empirically validates the LTP method's accuracy and reliability for assessing femoral rotation in surgical settings.

## Key findings

- Accuracy of the LTP method was within 3° for all observer groups.
- Interobserver reliability was very high with ICC values greater than 0.99.
- Medical students required more attempts than fellowship-trained surgeons but still achieved accurate results.

## Abstract

Introduction: The lesser trochanter profile (LTP) method is an intraoperative fluoroscopic technique that can assess the femoral version and limit malrotation. The purpose of this study was to directly assess the accuracy and reliability of the LTP method, as well as determine the incidence of malrotation produced by this technique. Methods: Three groups of observers (fellowship-trained orthopedic surgeons, orthopedic residents, and medical students) utilized the LTP method to replicate pre-imaged rotation angles on a cadaveric femur bone. Recorded outcomes include rotational error and number of attempts. Accuracy and interobserver reliability were assessed by rotational error and the interclass correlation coefficient (ICC), respectively. Results: Accuracy was within 3° for all three groups. ICC between each group was greater than 0.99. There was no statistical difference between the accuracy of fellowship-trained surgeons, orthopedic residents, and medical students. Medical students on average required more attempts to obtain their final image compared to fellowship-trained surgeons. There was no statistical difference in the number of attempts between residents and fellowship-trained surgeons. Conclusion: None of the LTP measurements were greater than 15°, the clinical threshold for malrotation. The average error of the observers was less than 3°, demonstrating that the LTP is an effective method of assessing the femoral version. There was no statistically significant difference between the observers, indicating that this technique is reliable and easy to use. Ultimately, the LTP method is easily reproducible for surgeons to avoid femoral malrotation.