FRI0626 DIFFICULTIES WITH MAKING A FIST IN PATIENTS WITH CLINICALLY SUSPECT ARTHRALGIA; AN EARLY PHENOMENON PREDICTIVE FOR RA THAT IS RELATED TO MRI-DETECTED TENOSYNOVITIS
Authors: Fenne Wouters, Florus van der Giesen, Xanthe Matthijssen, Ellis Niemantsverdriet
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Difficulties with making a fist in patients presenting with recent-onset arthralgia of small joints, in whom there is no clinically detectable arthritis, is often considered a risk factor for the development of inflammatory arthritis. The fact that rheumatologists consider difficulties with making a fist a feature of imminent Rheumatoid Arthritis (RA) is also reflected by this sign being incorporated in the EULAR definition of arthralgia suspicious for progression to RA. However, to date there is little comprehension on its predictive value and underlying cause in patients with recent-onset arthralgia. <h3>Objectives</h3> This study was performed to 1) determine if difficulties making a fist is indeed predictive for the development of clinical arthritis, and 2) evaluate if this sign is associated with subclinical joint inflammation, detected by magnetic resonance imaging (MRI). <h3>Methods</h3> 566 patients presenting with recent-onset (&lt;1 year) arthralgia of small joints that were consecutively included in the Clinically Suspect Arthralgia (CSA) cohort were studied. At baseline the ability to completely close the fist (all fingertips touching the palm) was assessed at physical examination. Additionally, contrast-enhanced 1.5T MRI of wrist, 2<sup>nd</sup>-5<sup>th</sup> metacarpophalangeal (MCP) and 1<sup>st</sup>-5<sup>th</sup> metatarsophalangeal (MTP) joints was performed. MRIs were scored for synovitis, bone marrow edema (BME) and tenosynovitis in line with the RAMRIS. MRI-detected subclinical inflammation was considered present if it was more than observed in symptom-free controls from the general population in the same age-category (n=193). Patients were followed on the development of clinically detectable inflammatory arthritis identified at joint examination (median follow-up 19 months); none of the patients received DMARDs before the development of clinical arthritis. χ<sup>2</sup> tests, logistic and Cox proportional hazards regression were used as appropriate. <h3>Results</h3> At first presentation 12% of CSA-patients had difficulties making a fist with one or both hands. Having difficulties making a fist was predictive for development of clinical arthritis in univariable analysis (HR 2.47 (95% CI 1.46-4.19)) and in multivariable analysis (HR 2.16 (1.25-3.74) corrected for age, CRP, ACPA and MRI-detected subclinical inflammation). Patients with difficulties making a fist had significantly more often MCP tenosynovitis (flexor tenosynovitis and extensor peritendinitis combined) than patients who did not experience these problems (42% versus 16%, p&lt;0.001). The main difference was seen in MCP flexor tenosynovitis (39% versus 10%, p&lt;0.001). MCP flexor tenosynovitis was significantly associated with difficulties making a fist in univariable (OR 5.6 (95% CI 3.2-9.9)), and multivariable regression (OR 5.7 (3.2-10.2) corrected for extensor peritendinitis, synovitis and BME in MCP joints). Extensor peritendinitis, synovitis and BME in MCP joints were not associated with difficulties making a fist (multivariable OR 0.7 (0.2-2.1), 0.99 (0.5-2.1) and 1.6 (0.7-4.1), respectively). <h3>Conclusion</h3> Difficulties making a fist in patients with CSA is predictive for future inflammatory arthritis development. This sign is presumably caused by MCP flexor tenosynovitis in a significant proportion of patients. <h3>Disclosure of Interests</h3> Fenne Wouters: None declared, Florus van der Giesen: None declared, Xanthe Matthijssen: None declared, Ellis Niemantsverdriet: None declared, Annette van der Helm - van Mil Grant/research support from: The research leading to these results has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Starting grant, agreement No 714312) and from the Dutch Arthritis Foundation. The funding source had no role in the design and conduct of the study.