In patients with recent-onset small joint arthralgia, incomplete fist closure is a valuable indicator to assess patients for underlying flexor tenosynovitis and a predictor of rheumatoid arthritis (RA) development, according to a research letter published in the Annals of the Rheumatic Diseases.

The European League Against Rheumatism developed a set of clinical characteristics to identify patients with arthralgia who are at risk for progression to RA. Although fist closure is one of these indicators, there is, according to researchers, “barely scientific evidence for its predictive value” and limited understanding of the underlying mechanisms.

The investigators reviewed existing studies, including one that examined patients (N = 606) with recent onset (<1 year) arthralgia of the small joints. At baseline, the researchers evaluated participants’ ability to completely close their fists, defined as actively closing the fist with all fingertips touching the palm, and fist strength, which was measured by the patient squeezing the assessor’s fingers. In addition, they performed contrast-enhanced magnetic resonance imaging (MRI) of the wrist and second to fifth metacarpophalangeal (MCP) joints. The investigators evaluated the MRI images and scored them for synovitis, bone marrow edema, tenosynovitis, and MCP extensor peritendinitis.

Of this cohort, 14% (hazard ratio [HR] 2.22; 95% CI, 1.36-3.64) had incomplete fist closure and 38% (HR 1.33; 95% CI, 0.87-2.05) had decreased fist strength). Both of these characteristics were independently associated with the development of inflammatory arthritis (HR 2.33; 95% CI, 1.38-3.93 and 1.62; 95% CI, 1.04-2.54, respectively).

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Researchers of the current study evaluated whether these fist problems could be associated with subclinical inflammation. Both fist closure and fist strength were related to symptoms; specifically, incomplete fist closure was associated with MCP flexor tenosynovitis and wrist flexor and extensor tenosynovitis (odds ratio [OR] 3.79; 95% CI, 2.04-7.04), and decreased fist strength was associated with MCP and wrist flexor tenosynovitis (OR 2.79; 95% CI, 1.52-5.12). Of the 2 tests, fist closure was a more reliable predictive value.

“Difficulties making a fist in recent-onset arthralgia in the absence of clinically apparent arthritis is considered a sign of imminent RA,” the researchers wrote. “This is the first study providing scientific support for the predictive value of this sign.”

They concluded, “In contrast to MRI, fist closure is simple to assess… Therefore, fist closure… is a feasible and valuable sign for use in daily clinical practice.”

Reference

Wouters F, van der Giesen FJ, Matthijssen XME, Niemantsverdriet E, van der Helm-van Mil AHM. Difficulties making a fist in clinically suspect arthralgia: an easy applicable phenomenon predictive for RA that is related to flexor tenosynovitis[published online May 2, 2019]. Ann Rheum Dis. doi:10.1136/annrheumdis-2019-215402