Impaired foot function may jeopardize the mobility of patients with rheumatoid arthritis (RA). However, there are still no guidelines concerning the adequate early treatment of painful rheumatoid feet which do not yet require surgery. An assessment method for RA feet appears necessary in order to detect foot problems before functional limitations develop. Therefore, the aim of the present study was to evaluate the use of pedobarographic measurements for detecting changes in plantar loading characteristics and their relationship to foot pain in patients with RA.
One hundred and twelve patients with RA (55.0+/-11.0 years of age) were divided into three groups according to their Health Assessment Questionnaire (HAQ) Score and compared to a control group of 20 healthy adults (CG). Thirty-six patients with good physical capacity belonged to group 1 (RA1; HAQ-score: 0-1.0), 38 patients with moderate capacity to group 2 (RA2; score: 1.1-2.0) and 38 patients with low capacity to group 3 (RA3; score: 2.1-3.0). Each patient's foot pain was clinically assessed. Pedobarography was used to analyze foot loading parameters while walking barefoot.
In the forefoot, average pressures under the lateral forefoot were higher in RA1 patients than in RA2 patients and controls (p<0.05) despite an inconspicuous clinical examination of the foot in RA1 patients. RA1 patients also demonstrated higher plantar pressures than RA2 under the second metatarsal head (p<0.05). In contrast, no significant differences in maximum force could be demonstrated between patient groups. Furthermore, in RA3 patients with lower physical capacity, foot pain was increased as compared to RA1 and RA2 patients.
In RA patients, pedobarographic patterns show specific changes which characterize the level of functional capacity. In patients with foot involvement, pedobarographic measurements can be useful during the earlier stages of the disease, when clinical examination does not yet indicate the need for more aggressive treatment or orthopedic interventions.