UCSF

Background

Femoral derotation osteotomies are commonly performed to correct rotational disorders of the hip in children. Surgical correction is typically assessed visually with the use of a goniometer or osteotomy template, but these methods have been shown to be inaccurate. In this study, we aimed to determine the accuracy of an electronic inclinometer in performing derotation osteotomies of 2 different magnitudes in comparison to commonly used visual techniques.

Methods

We performed derotation osteotomies of 15°and 30° in a synthetic femur model using a goniometer, triangle osteotomy template, and electronic inclinometer. The degree of derotation was assessed by computed tomography (CT) and measured by a musculoskeletal radiologist. Statistical analyses included descriptive statistics, as well as t-test, analysis of variance (ANOVA), and Fisher's exact test to determine differences between osteotomy techniques.

Results

We performed 40 proximal femoral derotation osteotomies. The mean difference from the planned derotation was 5.9° for the goniometer technique, 3.8° for the osteotomy triangle technique, and 3.2° for the electronic inclinometer technique (p-value = 0.048). There was no difference between the techniques for 15° derotation osteotomies (p-value = 0.28); however, there was a trend towards significance for 30° derotation osteotomies (p-value = 0.07). Fewer osteotomies had a difference greater than 3° from the planned derotation using the electronic inclinometer technique (p-value = 0.04).

Conclusions

The accuracy of derotation osteotomies can be improved with the use of an electronic inclinometer. This technology has the potential to improve surgical technique, minimize surgical error, and possibly improve patient outcomes.