title: Global rotation has high sensitivity in ACL lesions within stress MRI.
abstract: OBJECTIVE
  This study aims to objectively compare side-to-side differences of P-A laxity alone and coupled with rotatory laxity within magnetic resonance imaging, in patients with total anterior cruciate ligament (ACL) rupture.
  
  
  METHODS
  This prospective study enrolled sixty-one patients with signs and symptoms of unilateral total anterior cruciate ligament rupture, which were referred to magnetic resonance evaluation with simultaneous instrumented laxity measurements. Sixteen of those patients were randomly selected to also have the contralateral healthy knee laxity profile tested. Images were acquired for the medial and lateral tibial plateaus without pressure, with postero-anterior translation, and postero-anterior translation coupled with maximum internal and external rotation, respectively.
  
  
  RESULTS
  All parameters measured were significantly different between healthy and injured knees (P < 0.05), with exception of lateral plateau without stress. The difference between injured and healthy knees for medial and lateral tibial plateaus anterior displacement (P < 0.05) and rotation (P < 0.001) was statistically significant. It was found a significant correlation between the global rotation of the lateral tibial plateau (lateral plateau with internal + external rotation) with pivot-shift, and between the anterior global translation of both tibial plateaus (medial + lateral tibial plateau) with Lachman. The anterior global translation of both tibial plateaus was the most specific test with a cut-off point of 11.1 mm (93.8 %), and the global rotation of the lateral tibial plateau was the most sensitive test with a correspondent cut-off point of 15.1 mm (92.9 %).
  
  
  CONCLUSIONS
  Objective laxity quantification of ACL-injured knees showed increased sagittal laxity, and simultaneously in sagittal and transversal planes, when compared to their healthy contralateral knee. Moreover, when measuring instability from anterior cruciate ligament ruptures, the anterior global translation of both tibial plateaus and global rotation of the lateral tibial plateau add diagnostic specificity and sensitivity. This work strengthens the evidence that the anterior cruciate ligament plays an important biomechanical role in controlling the anterior translation, but also both internal and external rotation. The high sensitivity and specificity of this device in objectively identifying and measuring the multiplanar instability clearly guides stability restoration clinical procedures. Level of evidence Cross-sectional study, Level III.
authors.affiliation: Orthopaedics Department of Minho University, Braga, Portugal. espregueira@dhresearchcentre.com.|Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal. espregueira@dhresearchcentre.com.|Dom Henrique Research Centre, Porto, Portugal. espregueira@dhresearchcentre.com.|3B's Research Group-Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal. espregueira@dhresearchcentre.com.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal. espregueira@dhresearchcentre.com.
authors.forename: João
authors.initials: J
authors.lastname: Espregueira-Mendes
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|Dom Henrique Research Centre, Porto, Portugal.|Faculty of Sports, University of Porto, Porto, Portugal.
authors.forename: Renato
authors.initials: R
authors.lastname: Andrade
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|Dom Henrique Research Centre, Porto, Portugal.|CMEMS Center for MicroElectroMechanical Systems, Mechanical Engineering Department, University of Minho, Guimarães, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Leal
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|Dom Henrique Research Centre, Porto, Portugal.|Orthopaedic Department, Centro Hospitalar Póvoa de Varzim, Vila do Conde, Portugal.
authors.forename: Hélder
authors.initials: H
authors.lastname: Pereira
authors.affiliation: Hospital do Coração, São Paulo, Brazil.|Musculoskeletal Department, Clínica Alta Excelência Diagnóstica, São Paulo, Brazil.
authors.forename: Abdala
authors.initials: A
authors.lastname: Skaf
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|Dom Henrique Research Centre, Porto, Portugal.|SMIC Group, Porto, Portugal.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Rodrigues-Gomes
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|3B's Research Group-Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: J Miguel
authors.initials: JM
authors.lastname: Oliveira
authors.affiliation: 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
authors.affiliation: Clínica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence, Porto, Portugal.|Dom Henrique Research Centre, Porto, Portugal.|Faculty of Health Sciences, University of Fernando Pessoa, Porto, Portugal.
authors.forename: Rogério
authors.initials: R
authors.lastname: Pereira
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D016059:Range of Motion, Articular; D012399:Rotation; D012680:Sensitivity and Specificity
keywords: ACL; Instability; Knee; Magnetic resonance imaging; Rotatory laxity; Sagittal laxity