title: Usefulness of MR arthrography of the hip with leg traction in the evaluation of ligamentum teres injuries.
abstract: OBJECTIVE
  To retrospectively evaluate the diagnostic accuracy of magnetic resonance (MR) arthrography of the hip with leg traction in the evaluation of ligamentum teres lesions and to evaluate whether there is increased articular distraction, possibly indicating secondary instability, in hips with ligamentum teres injuries.
  
  
  METHODS
  Institutional review board approval and informed consent were obtained for this retrospective study. MR arthrograms of the hip with leg traction of 184 consecutive patients, including 108 men (mean age, 32.6 years; range, 19-53 years) and 76 women (mean age, 38.5 years; range, 18-56 years), who underwent hip arthroscopy were assessed for the presence of ligamentum teres lesions. The MR arthrographic findings were independently assessed by two radiologists who were blinded to the arthroscopic results. The inclusion criteria stipulated no previous surgery, arthroscopy within 1 month after MR arthrography, and availability of a detailed surgical report with ligamentum teres findings. The arthroscopy findings served as the reference standard. Sensitivity, specificity, accuracy, and K statistics for interobserver and intraobserver agreement were calculated.
  
  
  RESULTS
  At arthroscopy, 32 ligamentum teres injuries were found. The ligamentum teres was normal in 152 (82.6%) patients and had suffered low-grade partial tears in 15 (8.1%) patients, high-grade partial tears in 10 (5.4%) patients, and complete ruptures in 7 (3.8%) patients. MR arthrography with axial traction demonstrated moderate sensitivity and high specificity for both low-grade (62/93%) and high-grade (66/96%) partial tears. Grouping low- and high-grade partial tears increased the diagnostic performance of MR arthrography, yielding a sensitivity of 87% and a specificity of 95%. For complete ligamentum teres tears, MR arthrography with leg traction demonstrated high sensitivity (92%) and specificity (98%). Articular distraction was significantly increased in patients with complete ruptures of the ligamentum teres (p = 0.001).
  
  
  CONCLUSIONS
  MR arthrography with leg traction offers accurate diagnosis of ligamentum teres injuries. Patients with complete tears of the ligamentum teres exhibit increased articular distraction that may indicate secondary hip instability.
authors.affiliation: Department of Radiology, Diagnóstico Médico Cantabria, Calle Castilla 6 Bajo, 39002, Santander, Cantabria, Spain. lcerezal@gmail.com.
authors.forename: Luis
authors.identifier: http://orcid.org/0000-0002-4934-0255
authors.initials: L
authors.lastname: Cerezal
authors.affiliation: Learnig Trauma Med. Centro de Consultas Médicas CCM, Orthopedic Surgery department, Santander, Spain.
authors.forename: Luis Pérez
authors.initials: LP
authors.lastname: Carro
authors.affiliation: University of Cantabria - IDIVAL, Santander, Spain.|CIBER Epidemiology and Public Health, Santander, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Llorca
authors.affiliation: Department of Radiology, Diagnóstico Médico Cantabria, Calle Castilla 6 Bajo, 39002, Santander, Cantabria, Spain.
authors.forename: Moisés
authors.initials: M
authors.lastname: Fernández-Hernando
authors.affiliation: Department of Radiology, Alzira Hospital, Valencia, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Llopis
authors.affiliation: Anatomy and Cell Biology, Cantabria University, Santander, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Montero
authors.affiliation: Anatomy and Cell Biology, Cantabria University, Santander, Spain.|Department of Radiology Marqués de Valdecilla University Hospital, Santander, Cantabria, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Canga
mesh_terms: D000293:Adolescent; D000328:Adult; D001175:Arthrography; D005260:Female; D025981:Hip Injuries / Q000473:pathology*; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007866:Leg; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D000069590:Round Ligaments / Q000293:injuries* / Q000473:pathology*; D012680:Sensitivity and Specificity; D014143:Traction; D055815:Young Adult
keywords: Hip arthroscopy; Hip injuries; Hip pain; Instability; Ligamentum teres; Ligamentum teres pathology; MR arthrography