Foot Structure Linked to Foot Pain in Psoriatic Arthritis Patients

For psoriatic arthritis patients (PsA), foot pain and inflammation are tied to foot structure, according to research published in the April 2014 issue of Rheumatology.

While observing the metatarsophalangeal (MTP) joints of 34 PsA patients and 22 healthy patients, researchers from the Glasgow Caledonian University analyzed a total of 340 MTP joints in the PsA groups and 220 in the control group. The subjects’ pain, swelling, plantar pressure, and erosion were also recorded at the MTP joints.

PsA patients reported 129 painful joints, while control patients reported no joint pain. Additionally, the researchers found PsA patients had a higher rate of subluxation and deformity in their joints compared to healthy patients. They also noted that body mass index (BMI) and gender (female) also influenced foot structure and pain. However, plantar pressure was not associated with MTP pain in PsA patients.

“Effusion was the most prevalent US feature in both groups (46% PsA versus 41% control),” the authors wrote. “The prevalence of synovitis and erosion were both 14% in the PsA group, while these were absent in the control group. For these features, additional tests revealed that these group differences were consistent between joints, i.e. not linked to a specific joint location.”

Despite the study’s limitations, the authors believed their findings showed an association between physical and mechanical factors that can be translated to other arthritic ailments.

“This work supports an explanatory model of peripheral joint pain in PsA that includes local inflammatory and structural factors as well as systemic characteristics (gender, BMI),” the researchers concluded.