Site specific osteoarthritis and the index to ring finger length ratio

Ferraro, B.; Wilder, F.V.; Leaverton, P.E.

doi:10.1016/j.joca.2009.11.001

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Volume 18, Issue 3 , Pages 354-357, March 2010

Site specific osteoarthritis and the index to ring finger length ratio

B. Ferraro
- University of South Florida College of Public Health, Department of Epidemiology and Biostatistics, Tampa, FL 33612, USA
- University of South Florida College of Medicine, Department of Molecular Medicine, Tampa, FL 33612, USA
F.V. Wilder
- University of South Florida College of Public Health, Department of Epidemiology and Biostatistics, Tampa, FL 33612, USA
- The Arthritis Research Institute of America, Clearwater, FL 33755, USA
- Address correspondence and reprint requests to: Frances V. Wilder, The Arthritis Research Institute of America, 300 South Duncan Avenue, Suite 188, Clearwater, FL 33755, USA. Tel: 1-727-46104054; Fax: 1-727-449-9227.
P.E. Leaverton
- University of South Florida College of Public Health, Department of Epidemiology and Biostatistics, Tampa, FL 33612, USA
- The Arthritis Research Institute of America, Clearwater, FL 33755, USA

Received 10 June 2009; accepted 1 October 2009. published online 23 November 2009.

Summary

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 ≥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.

Key words: Digit ratio, Osteoarthritis