Correspondence on 'Role of joint damage, malalignment and inflammation in articular tenderness in rheumatoid arthritis, psoriatic arthritis and osteoarthritis'

With great interest we read the article of Gessl et al that studied whether tenderness of non-swollen small hand joints was explained by subclinical inflammation as detected by ultrasound (US). Interestingly, the findings in rheumatoid arthritis (RA) were dependent on the disease stage: tenderness in longstanding RA (mean disease duration 7.2 years) was not associated with subclinical inflammation, while in early RA (disease duration <2 years) tenderness of hand joints was associated with subclinical inflammation (54.5% of tender joints vs 48.4% of non-tender joints showed inflammation; OR 2.22).1 Since validation of research findings is of utmost importance, we hypothesised that the findings observed in early clinical RA would correspond to similar findings in the symptomatic phase that precedes clinical inflammatory arthritis and RA.2 It is important to understand whether joint tenderness in patients with clinically suspect arthralgia (CSA) is related to subclinical inflammation, since joint swelling is per definition absent in this phase. This prompted us to perform a validation study in CSA patients. We studied the association of joint tenderness in metacarpophalangeal (MCP) joints with subclinical inflammation as determined by MRI. We focused on MCP joints since these joints are included in the EULAR definition of arthralgia suspicious for progression to RA.3 On …