title: Reproducibility and reliability of the outerbridge classification for grading chondral lesions of the knee arthroscopically.
abstract: BACKGROUND
  Few studies have investigated the accuracy and reproducibility of the Outerbridge classification system for classification of chondral damage in the knee.
  
  
  OBJECTIVE
  Arthroscopically assigned Outerbridge grades are accurate, reliable, and reproducible.
  
  
  METHODS
  Cadaver study.
  
  
  METHODS
  Six cadaveric knees underwent diagnostic arthroscopy, which was videotaped. An arthrotomy was then performed and the arthroscopically identified lesions were measured with calipers. Nine orthopaedic surgeons reviewed each video and graded each chondral lesion two separate times. Accuracy of observations was calculated based on the percentage of agreement between the grades determined during arthroscopy and arthrotomy.
  
  
  RESULTS
  The overall accuracy was 68% but varied by location. The kappa coefficient between the two scores was 0.602; the arthroscopy grade was higher than the arthrotomy grade 63% of the time. The intraobserver and interobserver kappa coefficients were 0.80 and 0.52, respectively. The mean interobserver kappa between the two physicians in practice 5 years or more was 0.72, compared with 0.50 for physicians in practice less than 5 years.
  
  
  CONCLUSIONS
  The Outerbridge classification was moderately accurate when used to grade chondral lesions arthroscopically.
  
  
  CONCLUSIONS
  Orthopaedic surgeons can accurately grade chondral lesions of the knee with the Outerbridge classification, regardless of their level of experience.
authors.affiliation: Steadman-Hawkins Sports Medicine Foundation, Vail, Colorado, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Cameron
authors.forename: Karen K
authors.initials: KK
authors.lastname: Briggs
authors.forename: J Richard
authors.initials: JR
authors.lastname: Steadman
mesh_terms: D000368:Aged; D001182:Arthroscopy; D002102:Cadaver; D002358:Cartilage, Articular / Q000293:injuries* / Q000473:pathology*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000145:classification* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013223:Statistics as Topic / Q000379:methods; D014743:Videotape Recording