title: Histologic/histochemical grading system for osteoarthritic articular cartilage: reproducibility and validity.
abstract: OBJECTIVE
  To evaluate the reproducibility and validity of the histologic/histochemical grading system (HHGS) for osteoarthritis (OA) developed by Mankin and coworkers.
  
  
  METHODS
  Sections of human articular cartilage from macroscopically normal and osteoarthritic femoral heads were graded by the HHGS (0-14 scale) twice by 3 observers, and intra- and interobserver reproducibility was determined.
  
  
  RESULTS
  The exact intra- and interobserver reproducibilities ranged from 22% to 33% and from 13% to 25%, respectively. Intra- and interobserver variation ranged from -7 to 5. Although scores were generally higher in cartilage from osteoarthritic joints as compared with cartilage from normal joints, the difference reached statistical significance for only 2 observers. Additionally, the average scores from all observers were within the definitive range for OA (>5) in 30% of sections from normal joints, and in only 47% of sections from OA joints.
  
  
  CONCLUSIONS
  The results indicate that the reproducibility and the validity of the HHGS are inadequate, and an improved histopathologic grading system for OA is needed.
authors.affiliation: National University Hospital/Rigshospitalet, Copenhagen, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Ostergaard
authors.forename: J
authors.initials: J
authors.lastname: Petersen
authors.forename: C B
authors.initials: CB
authors.lastname: Andersen
authors.forename: K
authors.initials: K
authors.lastname: Bendtzen
authors.forename: D M
authors.initials: DM
authors.lastname: Salter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology*; D005069:Evaluation Studies as Topic; D005260:Female; D005270:Femur Head / Q000378:metabolism / Q000473:pathology; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012219:Rheumatology / Q000379:methods; D012680:Sensitivity and Specificity