Calcaneal involvement in rheumatoid arthritis and in a control group (X-ray study)

Abstract

To observe on X-ray, the heel in rheumatoid arthritis (RA) and in a control group, and observe the possible relations with flatfoot and other radiological symptoms. 302 feet (rheumatoid feet, RF) of 151 patients with RA are compared to 200 feet of 100 consecutive patients with simple neck pain (control group, CF). The RF and CF groups are homogeneous in sex, age and laterality of the foot. Lateral weight-bearing radiographs are obtained for each foot. Three ranges of angular variations which correspond to cavus foot, middle foot and flatfoot are observed. Several other radiological features are studied: plantar calcaneal exostosis (pCE), large pCE, posterior exostosis (PCE), large PCE, posterior calcaneitis, plantar calcaneitis and dorsal osteophytosis of the first metatarsal bone. The incidence of PCE is greater in RF than in CF on the whole (p = 0.005), before 50 years (p = 0.002) and (on the limit) after 50 years (p = 0.059). In RF, PCE is correlated with flatfoot (p = 0.03) and age (p = 0.048), but more significantly with disease duration (p = 0.001). The incidence of PCE increases more significantly with age in CF (p = 0.0005) than in RF. In CF the role of age seems to be more important than the role of flatfoot in the appearance of PCE. The plantar calcaneal exostosis is more frequent in the rheumatoid foot where it increases with flatfoot and age, and more significantly with disease duration. On the other hand, in control feet, the plantar calcaneal exostosis is more significantly correlated with age.