title: The value of colour Doppler sonography of the knee joint: a useful tool to discriminate inflammatory from non-inflammatory disease?
abstract: OBJECTIVE
  To determine the diagnostic value of colour Doppler ultrasound (CDUS) in patients with inflammatory arthritis (IA) vs non-inflammatory disease (e.g. OA) of the knee joint.
  
  
  METHODS
  Standardized CDUS examinations were performed in 111 knee joints of 106 patients (70 women and 36 men) presenting with severe OA (n = 72) or confirmed IA (n = 39) of one or both knee joints to determine the degree of synovial inflammation in a semiquantitative fashion. To definitely distinguish inflammatory from non-inflammatory disease, SF was obtained from every patient within 24 h after sonography and analysed SFs containing ≤1000 white blood cells (WBC)/µl were considered non-inflammatory, whereas ≥5000 WBC/µl were classified as inflammatory.
  
  
  RESULTS
  The CDUS sum score of OA patients was determined to be 3.3 (range 0-8). In contrast, IA patients exhibited significantly elevated synovitis score of 5.3 (range 3-9) (P < 0.001). However, high synovial CDUS activity could be observed in OA patients sporadically. Therefore, there is no definitive CDUS threshold that clearly separates OA from IA patients.
  
  
  CONCLUSIONS
  CDUS is a valuable instrument to assist clinicians in distinguishing OA from IA of the knee joint, but nevertheless should always be interpreted within the clinical context.
authors.affiliation: Department of Rheumatology/Clinical Immunology, Asklepios Clinic, Kaiser-Karl-V-Allee 3, D-93077 Bad Abbach, Germany.
authors.forename: Nelly
authors.initials: N
authors.lastname: Beitinger
authors.forename: Boris
authors.initials: B
authors.lastname: Ehrenstein
authors.forename: Benno
authors.initials: B
authors.lastname: Schreiner
authors.forename: Martin
authors.initials: M
authors.lastname: Fleck
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.forename: Christian
authors.initials: C
authors.lastname: Lüring
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hartung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000473:pathology; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000473:pathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013583:Synovial Membrane / Q000000981:diagnostic imaging / Q000473:pathology; D013585:Synovitis / Q000000981:diagnostic imaging / Q000473:pathology; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D055815:Young Adult
keywords: arthritis; knee; osteoarthritis; power Doppler ultrasound; synovial fluid analysis