title: Radiographic classification of osteoarthritis in commonly affected joints of the foot.
abstract: OBJECTIVE
  To develop a radiographic atlas for the classification of osteoarthritis (OA) in commonly affected joints of the foot based on observations of osteophytes and joint space narrowing, and to assess its intra- and inter-examiner reliability.
  
  
  METHODS
  Weightbearing dorso-plantar and lateral foot radiographs from people aged over 65 years were examined, and an atlas was developed incorporating characteristic OA features of five foot joints: the first metatarsophalangeal joint, the first cuneo-metatarsal joint (1(st) CMJ), the second cuneo-metatarsal (2(nd) CMJ), the navicular-first cuneiform joint and the talonavicular joint. To assess the reliability of the atlas, two examiners independently rated 50 radiographs on two separate occasions.
  
  
  RESULTS
  Observations using the atlas demonstrated moderate to excellent reliability within examiners (percentage agreement from 86 to 99% and weighted kappa from 0.45 to 0.95), and, with the exception of joint space narrowing of the 2(nd) CMJ from the lateral projection, fair to excellent reliability between examiners (percentage agreement from 86 to 97% and weighted kappa from 0.32 to 0.87). Intra-class correlation coefficients for the overall foot OA score (representing the sum of observations for all joints from both feet) ranged between 0.83 and 0.89 for intra-examiner comparisons, and between 0.72 and 0.74 for inter-examiner comparisons.
  
  
  CONCLUSIONS
  Radiographic features of OA in commonly affected foot joints can be documented with high levels of agreement within examiners and moderate levels of agreement between examiners. Provided single examiners or consensus gradings are used, the atlas appears to be a useful tool to assist in the standardization of foot OA assessment for epidemiological and clinical studies.
authors.affiliation: Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Bundoora, Victoria 3086, Australia. h.menz@latrobe.edu.au
authors.forename: H B
authors.initials: HB
authors.lastname: Menz
authors.forename: S E
authors.initials: SE
authors.lastname: Munteanu
authors.forename: K B
authors.initials: KB
authors.lastname: Landorf
authors.forename: G V
authors.initials: GV
authors.lastname: Zammit
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging*; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000145:classification* / Q000000981:diagnostic imaging*; D011859:Radiography; D015203:Reproducibility of Results