title: Risk factors for early radiographic changes of tibiofemoral osteoarthritis.
abstract: OBJECTIVE
  To evaluate the risk factors for early radiographic changes of knee osteoarthritis.
  
  
  METHODS
  
  
  
  METHODS
  (n = 114) with unilateral or bilateral grade 0-1 knee osteoarthritis underwent x ray examination of the knees (semiflexed anteroposterior view) and assessment with the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index at baseline and 30 months later. Severity of joint space narrowing (JSN) and osteophytosis were graded in randomly ordered serial radiographs by two readers, blinded to the sequence of the films, using standard pictorial atlases.
  
  
  RESULTS
  The odds of an initial appearance of radiographic features of knee osteoarthritis at month 30 were more than threefold greater in African Americans than in whites (osteophytosis: odds ratio (OR) 3.30, 95% confidence interval (CI) 1.04 to 10.54; JSN: OR 3.49, 95% CI 1.16 to 10.68). In addition, the appearance of osteophytosis was positively related to baseline stiffness (OR 1.91/2.1 points on the 2-10 WOMAC scale, 95% CI 1.29 to 2.82).
  
  
  CONCLUSIONS
  The distinction between incident and established, but early, radiographic knee osteoarthritis is difficult because of the limits to which all possible evidence of the disease can be ruled out in a conventional baseline knee radiograph. Nonetheless, our finding that African Americans were at greater risk of early osteophytosis and JSN than other subjects differs from the results of our previous analysis of risk factors for progressive knee osteoarthritis in the same subjects. The development of osteophytes also was associated with joint stiffness. Future investigations should focus on the systemic and local influences that these ostensible risk factors represent.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202-5100, USA. smazzuca@iupui.edu
authors.forename: Steven A
authors.initials: SA
authors.lastname: Mazzuca
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Brandt
authors.forename: Barry P
authors.initials: BP
authors.lastname: Katz
authors.forename: Yan
authors.initials: Y
authors.lastname: Ding
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Lane
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Buckwalter
mesh_terms: D001741:Black or African American; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000208:ethnology / Q000473:pathology; D011859:Radiography; D012307:Risk Factors; D012720:Severity of Illness Index