title: Diagnostic performance of knee ultrasonography for detecting degenerative changes of articular cartilage.
abstract: OBJECTIVE
  To investigate the diagnostic performance of non-invasive knee ultrasonography (US) to detect degenerative changes of articular cartilage using arthroscopic grading as the gold standard.
  
  
  METHODS
  Forty adult patients referred to a knee arthroscopy because of knee pain were randomly selected for the study. Before the arthroscopy, knee US was performed and cartilage surfaces at medial and lateral femoral condyles as well as at intercondylar notch area (sulcus) were semi-quantitatively graded from US. Ultrasonographic grading was compared with the arthroscopic Noyes' grading for cartilage degeneration.
  
  
  RESULTS
  Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic odds ratio for detecting arthroscopic cartilage changes in US varied between 52 and 83%, 50-100%, 88-100%, 24-46%, and 5.0-13.0, respectively, depending on the site. Correlation of severity of cartilage changes (grades) between US and arthroscopy varied from insignificant to significant depending on the site: at the sulcus area the correlation was highest (r(s)=0.593, P<0.001), at the medial condyle also significant (r(s)=0.465, P=0.003), and at the lateral condyle non-significant (r(s)=0.262, P=0.103). The sum of cartilage grades in all three sites of the femoral cartilage between US and arthroscopy had the highest correlation (r(s)=0.655, P<0.001).
  
  
  CONCLUSIONS
  Positive finding in US is a strong indicator of arthroscopic degenerative changes of cartilage, but negative finding does not rule out degenerative changes. Non-invasive knee US is a promising technique for screening of degenerative changes of articular cartilage, e.g., during osteoarthritis.
authors.affiliation: Department of Medical Technology, Institute of Biomedicine, University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, University of Oulu and Oulu University Hospital, Oulu, Finland. Electronic address: simo.saarakkala@oulu.fi.
authors.forename: S
authors.initials: S
authors.lastname: Saarakkala
authors.affiliation: Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Waris
authors.affiliation: Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: V
authors.initials: V
authors.lastname: Waris
authors.affiliation: Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Tarkiainen
authors.affiliation: Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Karvanen
authors.affiliation: Department of Medical Physics, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Aarnio
authors.affiliation: Department of Internal Medicine, Mikkeli Central Hospital, Mikkeli, Finland.
authors.forename: J M
authors.initials: JM
authors.lastname: Koski
mesh_terms: D000328:Adult; D000368:Aged; D001182:Arthroscopy / Q000379:methods; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014463:Ultrasonography