Foot deformities in patients with rheumatoid arthritis: the relationship with foot functions

Aim: The aim of this study was to investigate foot deformities in patients with rheumatoid arthritis (RA), to detect frequency of deformities and to assess the relationship between foot deformities and foot functions. Methods: Anteroposterior and lateral radiographs of 40 patients and 40 control subjects were studied. The hallux valgus (HV) angle, intermetatarsal angle between first and second metatarsals, intermetatarsal angle between first and fifth metatarsals, and calcaneal pitch were measured on radiographs. Foot functions were measured by the Foot and Ankle Outcome Score (FAOS). Results: The frequency of foot deformities in RA patients was determined as 78.8%. The most frequent foot deformity in RA patients was HV (62.5%), followed by metatarsus primus varus (MPV) (41.3%). MPV and splaying of the forefoot deformities were significantly more frequent in RA patients than the control group (P < 0.05). Mild to moderate effect on FAOS subscales was observed in RA patients. There was a slight, but significant correlation between the foot deformities and the FAOS subscales except for quality of life subscale. Conclusions: In this study, it has been shown that foot deformities are frequent in patients with RA and that there is slight deterioration in foot functions related to RA. Our results indicated that foot deformities have small, but clinically important changes on foot functions. There is a need for more studies, which evaluates the foot deformities, to further explore the relationship between the foot deformities and foot function in patients with RA.