LAUSR

Objectives Malrotation after surgical treatment of femoral shaft fractures is a common problem and often leads to follow-up procedures with uncertain outcome. The aim of this study is the validation of a new device (Rotational Fixator) to perform the correction safely and accurately. Methods In an in-vitro study, we tested the Rotational Fixator on 21 corpse bones against a commercially available standard goniometer for measurement inaccuracies. For this purpose, we varied the rotation width from 10 to 30° in inside and outside rotation. Results We found a small measurement inaccuracy of 1-2° with increasing rotation. The smallest differences are found at 10° IR with 0.9524° (SD ± 1.0713; p = 0.001) difference and 10° ER with at 0.5952° (SD ± 0.6823; p = 0.001) difference and increase up to 30° (IR 1.6667°, SD ± 1.7121, p < 0.000/ER 1.5000°, SD ± 1.0488, p < 0.000). Conclusions The measurement results of the device show a constant deviation from the gold standard but are constant in the measurement error and slightly in relation to the desired correction range, so that a further review of the device and further testing in in vivo studies makes sense. Levels of evidence Level 3.