Intermetatarsal bursitis identified in clinically suspect arthralgia

Lifestyle

About one-quarter of patients with clinically suspect arthralgia (CSA) have intermetatarsal bursitis (IMB), which is often accompanied by subclinical synovitis and tenosynovitis, according to a study published online Nov. 13 in Rheumatology.

Bastiaan T. van Dijk, from the Leiden University Medical Centre in the Netherlands, and colleagues performed a large magnetic resonance imaging (MRI) study to assess the occurrence and prognostic value of IMB in 577 CSA patients. Participants underwent contrast-enhanced MRI of the forefoot, metacarpophalangeal joints, and wrist; MRIs were assessed for subclinical synovitis/tenosynovitis/osteitis and for IMB. The association between IMB and other MRI-detected subclinical inflammation was assessed.

The researchers found that 23 percent of participants had IMB at presentation with CSA. In anti-citrullinated protein antibody (ACPA)-positive versus ACPA-negative CSA, IMB was more frequent (47 versus 19 percent). The likelihood of subclinical synovitis and tenosynovitis was increased for patients with IMB (odds ratios, 3.4 and 5.9, respectively). The risk of developing arthritis was increased with IMB (hazard ratio, 1.6) after adjustment for other subclinical inflammation. In ACPA-positive, but not ACPA-negative, CSA patients, IMB presence predicted arthritis development (adjusted hazard ratio, 2.2).

“IMB is detectable by MRI in a quarter of CSA-patients and is frequently accompanied by subclinical synovitis and tenosynovitis. In addition, IMB precedes development of clinical arthritis, particularly in ACPA-positive CSA,” the authors write. “These results reinforce the notion that juxta-articular synovial inflammation is involved in the earliest phases of arthritis development in rheumatoid arthritis.”