NEW YORK (Reuters Health), May 20 - Results of a study published in the April 15 issue of Arthritis and Rheumatism suggest that measuring finger joint cartilage by ultrasound is an effective alternative to conventional radiograph imaging.
"Loss of cartilage reflects irreversible joint destruction and contributes to impaired joint function in osteoarthritis and rheumatoid arthritis," Dr. Burkhard Moller and colleagues from University Hospital Berne, Switzerland, write. "Loss of cartilage in osteoarthritis is generally indirectly evaluated by radiologic assessment of joint space distance, together with evaluation of pathologic bone formation."
The researchers assessed the reliability and validity of ultrasound imaging to measure finger joint cartilage. A total of 124 subjects were included in the study: 48 had rheumatoid arthritis, 18 had osteoarthritis, 24 had unclassified arthritis of the finger joints, and 34 were healthy volunteers. The investigators visualized the proximal cartilage layer of metacarpophalangeal and proximal interphalangeal joints for fingers two to five bilaterally from a posterior view, with joints in approximately 90° flexion.
Precise measurement was not possible in 2.5% of metacarpophalangeal and 5.8% of proximal interphalangeal joints. The intraclass correlation coefficient for bilateral total joint ultrasound scores was 0.844 for interobserver comparisons. Intraobserver reliability was also high, with an intraclass correlation coefficient of 0.928.
Good correlation was observed between the ultrasound score and joint spacing narrowing for both hands (adjusted R2 = 0.513, p < 0.001) and joint space width of the same finger joints (adjusted R2 = 0.635, p < 0.001).
Ultrasound scores were significantly lower in patients with early symptomatic osteoarthritis than in those with early rheumatoid arthritis or with healthy joints. The authors report that ultrasound scores correlated with duration of treatment-resistant, progressive rheumatoid arthritis.
"Overall, the US method of cartilage measurement was shown to be a promising alternative to radiographic methods for estimating cartilage," Moller's team explains. "In addition to being reliable and valid, this method has several practical advantages (e.g., efficiency and cost) that make it valuable for use in both research and clinical practice."
Arthritis Rheum 2009;61:435-441.
Last Updated: 2009-05-19 15:48:14 -0400 (Reuters Health)
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