Background Musculoskeletal Ultrasound (US) is now becoming part of the daily practice of rheumatology. In fact, it is a useful tool in rheumatoid arthritis (RA) for detecting persisting infra-clinical synovitis in patients in remission. However, possible existence of a physiological effusion of the PIP was demonstrated in healthy subjects.
Objectives The purpose of our study was to assess the presence of US effusion in proximal interphalangeal (PIP) joints of RA patients in remission and to compare it to healthy controls.
Methods Thirty RA patients in remission (Disease Activity Score 28 joints <2,6 for at least 3 months) and 17 healthy control patients were prospectively enrolled. All of the patients had a musculoskeletal ultrasound (US) examination of the PIP of both hands from the second to the fifth. US (Esaote MyLab 60 machine and a 13-18 MHz linear array transducer) was performed by a rheumatologist with theoretical and practical training in musculoskeletal ultrasonography. The findings obtained by grey scale (GS) and PD were graded on a semi-quantitative scale from 0 to 3.
Results The mean age of RA patients in remission was 48 years-old and for control group 45 years-old. For the 240 joints scanned of RA patients, 37 (15%) joints presented synovitis in B mode and 9 (4%) a PD activity. Concerning control group, 136 joints were examined. Among them, 57 (42%) joints expressed synovitis in B mode and none in PD. The mean US score was 0,2 for RA patients and 0,5 for control group. The difference between two groups was significant (p=0,04).
Conclusions US activity can be detected in B mode but not in PD in PIP even in healthy subjects. Synovitis detected in PIP in RA patients even in remission must be taken into account when assessing the activity of the RA in order to avoid further damages and disabilities.
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Witt M. Relevance of grade 1 gray-scale ultrasound findings in wrists and small joints to the assessment of subclinical synovitis in rheumatoid arthritis. Arthritis Rheum. 2013
Disclosure of Interest None declared