title: Validity of histopathological grading of articular cartilage from osteoarthritic knee joints.
abstract: OBJECTIVE
  To determine the validity of the histological-histochemical grading system (HHGS) for osteoarthritic (OA) articular cartilage.
  
  
  METHODS
  Human articular cartilage was obtained from macroscopically normal (n = 13) and OA (n = 21) knee joints. Sections of central and peripheral regions of normal samples were produced. Sections of regions containing severe, moderate, and mild OA changes were produced from each OA sample. A total of 89 sections were graded by means of the HHGS (0-14) twice by three observers.
  
  
  RESULTS
  Average scores for regions designated severe (8.64) and moderate (5.83) OA were less than the expected (10-14 and 6-9, respectively) according to the HHGS, whereas average scores for the region designated mild (5.29) OA and central and peripheral regions (2.19) of normal cartilage were higher than expected (2-5 and 0-1, respectively). The HHGS was capable of differentiating between articular cartilage from macroscopically normal and OA joints and between the region designated severe OA and other regions. However, the HHGS did not adequately differentiate between regions designated mild and moderate OA. Values for sensitivity, specificity, and efficiency for all regions varied considerably.
  
  
  CONCLUSIONS
  The HHGS is valid for normal and severe OA cartilage, but does not permit distinction between mild and moderate OA changes in articular cartilage.
authors.affiliation: Osteoarthritis Research Unit, Institute for Inflammation Research, National University Hospital/Rigshospitalet, Copenhagen, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Ostergaard
authors.forename: C B
authors.initials: CB
authors.lastname: Andersen
authors.forename: J
authors.initials: J
authors.lastname: Petersen
authors.forename: K
authors.initials: K
authors.lastname: Bendtzen
authors.forename: D M
authors.initials: DM
authors.lastname: Salter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000473:pathology*; D004396:Coloring Agents; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology*; D010619:Phenazines; D015203:Reproducibility of Results
chemical_list: D004396:Coloring Agents; D010619:Phenazines; C009195:safranine T