title: MRI demonstrates the extension of juxta-articular venous malformation of the knee and correlates with joint changes.
abstract: OBJECTIVE
  Juxta-articular venous malformations (VMs) are uncommon, but may cause early arthropathy of the knee in children and adolescents. We sought to describe the prevalence, extent and initial magnetic resonance imaging (MRI) features of knee arthropathy in children with VM adjacent to the knee joint.
  
  
  METHODS
  Thirty-five patients with VM adjacent to the knee who had MRI performed between 2000 and 2009 were identified through a keyword search of the radiology information system.
  
  
  RESULTS
  VM extended to the joint in 17 of the 35 patients (5.4-21.5 years, mean 11.8 years). Most of these 17 patients had joint changes (15/17, 88%), most commonly haemosiderin deposition (14/17, 82%). Other findings included the presence of subchondral bone lesions (eight, 47%), cartilage loss (six, 35%), synovial thickening (six, 35%), marrow oedema (six, 35%), joint effusion (five, 29%), subchondral cysts (five, 29%) and one loose body (6%). VM location and size did not correlate with the degree of articular involvement. Joint changes were present in focal as well as non-discrete VM.
  
  
  CONCLUSIONS
  We found that the frequency of arthropathy increased with extension of VM into the joint itself. This finding stresses the importance of early MRI evaluation of all juxta-articular VM.
authors.affiliation: Department of Medical Imaging, University of Melbourne, Royal Children's Hospital, Parkville, Melbourne, Victoria, Australia. lennart.jans@rch.org.au
authors.forename: L
authors.initials: L
authors.lastname: Jans
authors.forename: M
authors.initials: M
authors.lastname: Ditchfield
authors.forename: J L
authors.initials: JL
authors.lastname: Jaremko
authors.forename: N
authors.initials: N
authors.lastname: Stephens
authors.forename: K
authors.initials: K
authors.lastname: Verstraete
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D007719:Knee Joint / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000254:growth & development; D008279:Magnetic Resonance Imaging; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D054079:Vascular Malformations / Q000000981:diagnostic imaging*; D055815:Young Adult
chemical_list: D003287:Contrast Media