title: Validity of rotational laxity coupled with anterior translation of the knee: A cadaveric study comparing radiostereometry and the Rotab®.
abstract: BACKGROUND
  In current practice, anterior cruciate ligament (ACL) tears can be diagnosed using several devices to measure anterior tibial translation and rotational knee laxity, but these measures are never collected together. The Rotab®, which yields simultaneous measurements of anterior tibial translation and passive lower limb rotation under stress, would therefore be advantageous in current practice, but its reliability has never been tested.
  
  
  OBJECTIVE
  To evaluate the accuracy and reliability of the Rotab® compared to the reference system, radiostereometric analysis (RSA).
  
  
  METHODS
  This anatomical study was conducted on 14 lower limbs collected from fresh cadavers. Simultaneous measurements of anterior tibial translation and rotation were obtained with both systems, with antero-posterior (AP) forces of 134N and 250N using the Rotab®. Measurements were made on intact ACL and then repeated after ACL section. Variables were analyzed in univariate analysis by ANOVA, and the intraclass correlation coefficient (ICC) between the systems was determined by the Bland and Altman method.
  
  
  RESULTS
  The difference between the two methods for evaluating anterior tibial translation was 0.05±0.98mm at 134N and 0.29±1.04mm at 250N. The correlation between the tests was high (r134=r250=0.97, p=0.8). The difference between the two methods for rotational laxity was 0.69±2.7° at 134N and 0.5±0.6° at 250N. The Rotab® showed a significant difference only at 250N for rotational laxity after the ACL tear.
  
  
  CONCLUSIONS
  The Rotab® is a reliable device to measure rotational laxity coupled with anterior translation of the knee.
authors.affiliation: Orthopedic Surgery and Traumatology Department, Rouen Teaching Medical Center, 76031 Rouen cedex, France. Electronic address: antoinesenioris@live.fr.
authors.forename: A
authors.initials: A
authors.lastname: Senioris
authors.affiliation: Orthopedic Surgery and Traumatology Department, Rouen Teaching Medical Center, 76031 Rouen cedex, France.
authors.forename: T
authors.initials: T
authors.lastname: Rousseau
authors.affiliation: CETAPS-EA 3832, Faculty of Sport Sciences, University of Rouen, 76821 Mont Saint Aignan, France.
authors.forename: M
authors.initials: M
authors.lastname: L'Hermette
authors.affiliation: Orthopedic Surgery and Traumatology Department, Rouen Teaching Medical Center, 76031 Rouen cedex, France; Orthopedic Surgery and Traumatology Department, University Hospital Center of Caen, U1075 Comete UCBN/INSERM, Medicine Faculty, Caen, France.
authors.forename: S
authors.initials: S
authors.lastname: Gouzy
authors.affiliation: Orthopedic Surgery and Traumatology Department, Rouen Teaching Medical Center, 76031 Rouen cedex, France; Anatomical Research Laboratory, Medicine Faculty, 22 Boulevard Gambetta, 76183 Rouen cedex 1, France.
authors.forename: F
authors.initials: F
authors.lastname: Duparc
authors.affiliation: Orthopedic Surgery and Traumatology Department, Rouen Teaching Medical Center, 76031 Rouen cedex, France; CETAPS-EA 3832, Faculty of Sport Sciences, University of Rouen, 76821 Mont Saint Aignan, France.
authors.forename: F
authors.initials: F
authors.lastname: Dujardin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000070598:Anterior Cruciate Ligament Injuries / Q000150:complications / Q000503:physiopathology*; D053587:Arthrometry, Articular; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D008875:Middle Aged; D059869:Radiostereometric Analysis; D015203:Reproducibility of Results; D012399:Rotation
keywords: Anterior cruciate ligament; Knee arthrometer; Radiostereometry; Reliability; Rotab®