Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Detection of Radiographic Progression in Early Knee Osteoarthritis (CHECK): Sensitivity to Change of Knee Images Digital Analysis Compared to Altman Grading.

Kinds3,  M. B., Bierma-Zeinstra1,  S. M. A., Marijnissen5,  A. C. A., Viergever2,  M. A., Bijlsma5,  J. W. J., Welsing4,  P. M. J., Lafeber5,  F. P. J. G.

General Practice, Erasmus University Rotterdam, the Netherlands
Image Sciences Institute, University Medical Center Utrecht, The Netherlands
Rheumatology & Clinical Immunology, Image Sciences Institute, University Medical Center Utrecht, The Netherlands
Rheumatology & Clinical Immunology, Julius Center for Health Sciences & Primary Care, University Medical Center Utrecht, The Netherlands
Rheumatology & Clinical Immunology, University Medical Center Utrecht, The Netherlands

Background:

In the detection of radiographic progression in osteoarthritis, semi-quantitative measurement commonly results in low sensitivity to change. Quantitative measurement of separate radiographic OA features using Knee Images Digital Analysis (KIDA)1 theoretically enables more precise measurement and greater sensitivity to change. In the longitudinal Cohort Hip & Cohort Knee (CHECK) radiographic progression is evaluated early in OA. The objective of this study was to determine whether the sensitivity to change of separate radiographic features of OA can be improved by using digital analysis (KIDA).

Methods:

Knee radiographs (PA semiflexed) were evaluated for the OA parameters: joint space narrowing (JSN; lateral and medial), osteophytes (lateral and medial femur, lateral and medial tibia), and bone density (BD; lateral femur and medial tibia) by quantitative measurement with KIDA and by semi-quantitative grading according to the Altman atlas2. For KIDA measurement sensitivity to change was determined by calculation of the smallest detectable difference (SDD), which accounts for the variability of the radiographic procedure and digital analysis. SDD was determined in a subset of unchanged knees from baseline to 2 year follow-up based on an Altman grade of 0 for all parameters at both time points (313, 303, and 213 pairs of knee radiographs for JSN, osteophyte area, and BD parameters respectively). Next, of all 1002 participants in CHECK available baseline and follow-up knee radiographs were evaluated. The percentage of knees changing on the radiographic parameters was determined for KIDA, defined as a change larger than the SDD, and for the Altman atlas defined as a change of at least one grade. Further, for each parameter knees with a change on KIDA and/or Altman were evaluated for agreement using cross-tabulations.

Results:

The SDD for the OA parameters in the different compartments ranged from 0.96 to 2.63mm for JSN, 1.30–4.89mm2 for osteophyte area, and 10.92–12.96mmAl equivalents for BD. Using KIDA, OA progression was found in 2.4–10.2% (JSN), 6.0–9.2% (osteophyte), and 2.2–4.8% (BD) of knees. Using Altman, OA progression was found in 4.1–11.0% (JSN), 3.3–10.6% (osteophyte), and 0.9–1.3% (BD) of knees. According to both KIDA and Altman, in two years of follow-up only in a limited number of knees radiographic progression occurred: e.g. 3% for JSN medial, and 2% for osteophytes at medial tibia. In 82% and 84% of knees no change occurred. In 15% of cases disagreement existed between knees changing according to KIDA measurement and the Altman atlas.

Conclusion:

Sensitivity to change for the detection of radiographic progression in early OA is not improved by using KIDA. Quality of acquisition of radiographs seems to be at least as important as quality of analysis.

References:

1.Marijnissen,  et al. OA&C. 2008 Feb;16(2):234-243;

2.Altman, , et al. OA&C. 2007;15(suppl A):A1–56

Sponsor:

CHECK is initiated by the Dutch Arthritis Association.

Acknowledgement:

Marja Lafeber is acknowledged for analyses of radiographs.

To cite this abstract, please use the following information:
Kinds, M. B., Bierma-Zeinstra, S. M. A., Marijnissen, A. C. A., Viergever, M. A., Bijlsma, J. W. J., Welsing, P. M. J., et al; Detection of Radiographic Progression in Early Knee Osteoarthritis (CHECK): Sensitivity to Change of Knee Images Digital Analysis Compared to Altman Grading. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :124
DOI: 10.1002/art.27893

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