Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


Assessment of Joint Cartilage Thickness by Ultrasound in Healthy Children: Age and Sex-Related Standard Reference Values

Spannow1,  Anne Helene, Pfeiffer-Jensen2,  Mogens, Andersen3,  Niels Trolle, Stenbog1,  Elisabeth, Herlin1,  Troels

Aarhus University Hospital Skejby, Aarhus N, Denmark
Aarhus University Hospital Aarhus Sygehus, Aarhus C, Denmark
Aarhus University, Aarhus C, Denmark

Purpose:

Loss of joint cartilage may be an early feature of destructive disease in juvenile idiopathic arthritis (JIA). When using conventional radiography early inflammatory changes are generally not detected and only late changes such as joint space narrowing and bone erosions are visualized. Joint cartilage is easily visualized with high frequency ultrasonography (US) but before US measurements of cartilage thickness is implemented there is a need for age- and sex-related normal standard reference values. The aim of the study was to establish age- and sex-related normal standard reference values for cartilage thickness US measurements in JIA target joints

Methods:

In 394 healthy Danish Caucasian children (215 boys/179 girls) we performed a cross-sectional study of bilateral greyscale US cartilage thickness measurements of the knee, ankle, wrist, and 2nd metacarpophalangeal (MCP) and 2nd proximal interphalangeal (PIP) joints making a total of 3940 joints investigated. Ultrasonographic settings: B-mode obtained on a real-time Hitachi EUB-6500 CFM scanner, equipped with a linear 6–13 MHz transducer (d-THI, frequency 14MHz, dynamic range 65), all measurements were obtained blinded and US images and cartilage thickness measurements for each child were stored on DVD. All statistics were performed with the STATA version 10 statistical package.

Results:

There was a significant difference in cartilage thickness measurements between sexes, (p<0.001 for all joints), boys having thicker cartilage compared to girls. Our results showed a clear decrease in cartilage thickness with increasing age for both sexes. A formula for calculating cartilage thickness for different ages and sexes in childhood was suggested. Given the estimate of the thickness y8 for a 8-years old child, the slope b and the standard deviation of the residual sdline an estimate of the thickness yx for a x-years old child can be calculated by yx= y8+b*(x-8) and a 95% PI by y8+b*(x-8) +/- 1.96 * sdline. No difference between the right and left side of the investigated joints was observed.

Difference in cartilage thickness between boys and girls age 7–16 years

 Difference boys–girls (mm)95% CI
Knee0.4710.383–0.559
Ankle0.1200.083–0.157
Wrist0.2570.185–0.328
MCP0.2560.221–0.291
PIP0.1240.098–0.149

Conclusion:

We have been able to establish age- and sex-related normal reference intervals for cartilage thickness measurements in the knee, ankle, wrist, and MCP and PIP joints with US for children with the age between 7 – 16 years and established a formula for calculation of hyaline cartilage thickness measurements in all age-groups throughout childhood.

To cite this abstract, please use the following information:
Spannow, Anne Helene, Pfeiffer-Jensen, Mogens, Andersen, Niels Trolle, Stenbog, Elisabeth, Herlin, Troels; Assessment of Joint Cartilage Thickness by Ultrasound in Healthy Children: Age and Sex-Related Standard Reference Values [abstract]. Arthritis Rheum 2009;60 Suppl 10 :254
DOI: 10.1002/art.25337

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