Table of Contents
International Scholarly Research Notices
Volume 2015, Article ID 705201, 7 pages
Research Article

Use of a Computed Tomography Based Approach to Validate Noninvasive Devices to Measure Rotational Knee Laxity

1Research Unit in Engineering Science, University of Luxembourg, 1359 Kirchberg, Luxembourg
2Fachhochschule Bingen, 55411 Bingen am Rhein, Germany
3Laboratoire de Biomécanique Appliquée, Université de la Méditerranée, 13916 Marseille, France
4Clinique d’Eich, Centre Hospitalier de Luxembourg, 1460 Eich, Luxembourg
5Chirurgisch-Orthopädisches Zentrum, Illingen, 66557 Saarland, Germany
6Klinik für Orthopädie und Orthopädische Chirurgie, Universitätsklinikum des Saarlandes, 66424 Homburg/Saar, Germany

Received 7 July 2015; Revised 14 October 2015; Accepted 3 November 2015

Academic Editor: Nadr Jomha

Copyright © 2015 Simon Neumann et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The purpose of this study is to validate a noninvasive rotational knee laxity measuring device called “Rotameter P2” with an approach based on Computed Tomography (CT). This CT-approach using X-rays is hence invasive and can be regarded as a precise reference method that may also be applied to similar devices. An error due to imperfect femur fixation was observed but can be neglected for small torques. The most significant estimation error is due to the unavoidable soft tissues rotation and hence flexibility in the measurement chain. The error increases with the applied torque. The assessment showed that the rotational knee angle measured with the Rotameter is still overestimated because of thigh and femur displacement, soft tissues deformation, and measurement artefacts adding up to a maximum of 285% error at +15 Nm for the Internal Rotation of female volunteers. This may be questioned if such noninvasive devices for measuring the Tibia-Femoral Rotation (TFR) can help diagnosing knee pathologies and investigate ligament reconstructive surgery.