A close up of a woman massaging her foot to help relieve pain.
Credit: fizkes/iStock

Rheumatoid arthritis (RA) is well-known for causing pain and inflammation in the hands, wrists, and knees, but it turns out that foot and ankle pain are also quite common. In fact,  69 percent of RA patients reported foot or ankle discomfort in a new study published in the journal ACR Open Rheumatology.

To conduct the study, researchers from Denmark analyzed data on 320 RA patients. Physicians assessed each patient using the DAS28, which is a disease activity measure that tracks the level of swelling and tenderness in 28 joints, as well as the 12-joint foot count, which checks for tender or swollen joints in the feet.

Clinicians also asked patients if they currently had any pain in their feet or ankles; those who said yes were given a short survey known as the Self-Reported Foot and Ankle Score (SEFAS) to report the pain in those areas.

According to the findings, nearly seven in 10 people with rheumatoid arthritis have foot and ankle pain, which often translates to more overall pain and trouble functioning. RA patients with foot and ankle pain are also more likely to have higher disease activity scores, but some patients in remission have this problem as well.

Although DAS28 has been criticized for not including the feet and ankles, this study found that adding the 12-joint foot count to the DAS28 was only marginally helpful, as 92 percent of patients with foot pain did not exhibit any swollen joints. Similarly, 61 percent of the patients who reported foot pain did not have any tender joints. Additionally, patients with self-reported foot and/or ankle problems often had trouble walking, but they did not necessarily have more inflamed joints in that area of the body.

The researchers explained that clinician assessment of the joints might fall short because, “foot and ankle pain in patients with rheumatoid arthritis does not necessarily originate from the examined joints; it could be present in other structures” like tendons and muscles, which are not factored into the 12-joint foot count.

These facts suggest that patient input about foot pain is critical.

“Joint examination should not stand alone,” the researchers wrote. “ Asking the patients about pain in their feet or ankles or including a [patient-reported outcome measure] will provide additional information on foot problems not identified by joint examinations.”

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Simonsen MB, et al. Foot and Ankle Problems in Patients With Rheumatoid Arthritis in 2019: Still an Important Issue. ACR Open Rheumatology. May 4, 2021. doi: https://doi.org/10.1002/acr2.11258.