title: Design, Repeatability, and Comparison to Literature Data of a New Noninvasive Device Called "Rotameter" to Measure Rotational Knee Laxity.
abstract: The present paper deals with the design, the repeatability, and the comparison to literature data of a new measuring device called "Rotameter" to characterize the rotational knee laxity or the tibia-femoral rotation (TFR). The initial prototype P1 of the Rotameter is shortly introduced and then modified according to trials carried out on a prosthetic leg and on five healthy volunteers, leading therefore to an improved prototype P2. A comparison of results obtained from P1 and P2 with the same male subject shows the enhancements of P2. Intertester and intratester repeatability of this new device were shown and it was observed that rotational laxities of left and right knees are the same for a healthy subject. Moreover, a literature review showed that measurements with P2 presented lower TFR values than other noninvasive devices. The measured TFR versus torque characteristic was quite similar to other invasive devices, which are more difficult to use and harmful to the patient. Hence, our prototype P2 proved to be an easy-to-use and suitable device for quantifying rotational knee laxity. A forthcoming study will validate the Rotameter thanks to an approach based on computed tomography in order to evaluate its precision.
authors.affiliation: Research Unit in Engineering Science, University of Luxembourg, 1359 Kirchberg, Luxembourg.
authors.forename: Simon
authors.initials: S
authors.lastname: Neumann
authors.affiliation: Research Unit in Engineering Science, University of Luxembourg, 1359 Kirchberg, Luxembourg.
authors.forename: Stefan
authors.identifier: 0000-0002-3941-1099
authors.initials: S
authors.lastname: Maas
authors.affiliation: Research Unit in Engineering Science, University of Luxembourg, 1359 Kirchberg, Luxembourg.
authors.forename: Danièle
authors.initials: D
authors.lastname: Waldmann
authors.affiliation: Research Unit in Engineering Science, University of Luxembourg, 1359 Kirchberg, Luxembourg.
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Ricci
authors.affiliation: Fachhochschule Bingen, 55411 Bingen am Rhein, Germany.
authors.forename: Arno
authors.initials: A
authors.lastname: Zürbes
authors.affiliation: Laboratoire de Biomécanique Appliquée, Université de la Méditerranée, 13916 Marseille, France.
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Arnoux
authors.affiliation: Chirurgisch-Orthopädisches MVZ, 66557 Illingen, Saarland, Germany; Klinik für Orthopädie und Orthopädische Chirurgie, Universitätsklinikum des Saarlandes, 66424 Homburg, Saarland, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kelm