title: Site specific osteoarthritis and the index to ring finger length ratio.
abstract: OBJECTIVE
  To quantify the relationship between the index to ring finger length ratio second digit:fourth digit(2D:4D) and radiographic osteoarthritis (OA) of the knee.
  
  
  METHODS
  Data from the Clearwater Osteoarthritis Study (COS) were analyzed. We selected a random sample of 236 subjects with knee OA (Kellgren-Lawrence scores >or=2) and compared their finger length ratio pattern with a random sample of 242 controls. Finger length measurements were recorded from digitized hand radiographs. Subjects were classified into three groups: type 1 (index finger longer than ring finger), type 2 (fingers of equal length) and type 3 (index finger shorter than ring finger). Using a case-control design, we calculated odds ratios (OR).
  
  
  RESULTS
  The type 3 finger pattern was significantly associated with knee OA (OR 2.59, 95% confidence interval (CI) 1.54-4.37). Women demonstrated a stronger association of visual type 3 finger pattern and knee OA (OR 4.40, 95% CI 2.62-7.38) compared to men (OR 2.59, 95% CI 1.34-5.00).
  
  
  CONCLUSIONS
  The type 3 finger length pattern is associated, to a statistically significant degree, with OA of the knee. The type 3 finger length pattern (ring finger longer than index finger) appears to be an indicator of OA predisposition. Consideration of this pattern in clinical assessments may be an added aid as clinicians screen patients for OA risk.
authors.affiliation: University of South Florida College of Public Health, Department of Epidemiology and Biostatistics, Tampa, FL 33612, USA.
authors.forename: B
authors.initials: B
authors.lastname: Ferraro
authors.forename: F V
authors.initials: FV
authors.lastname: Wilder
authors.forename: P E
authors.initials: PE
authors.lastname: Leaverton
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005384:Finger Joint / Q000033:anatomy & histology*; D005385:Fingers / Q000033:anatomy & histology*; D006225:Hand; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D012016:Reference Values; D012307:Risk Factors; D012737:Sex Factors