Clinical and Structural Associations of Disability and Gait Performance in Patients With Rheumatoid Arthritis in Remission and Metatarsal Pain.

BACKGROUND

Patients with rheumatoid arthritis (RA) may continue to experience foot-related disability despite clinical remission. Foot involvement is associated with self-reported disability and objective gait alterations. Foot involvement is heterogeneous; studying patients with localised forefoot pain may help clarify which structural and inflammatory factors are associated with functional impairment.

OBJECTIVES

To identify clinical, structural and imaging factors associated with disability and gait performance in patients with RA in clinical remission with metatarsal-region forefoot pain.

METHODS

Cross-sectional study of 81 patients with RA in remission with metatarsal-region forefoot pain. Outcomes were Foot Function Index disability and activity limitation (FFI-D and FFI-AL), gait velocity (GV) and double-support time (DS). Associations were examined using Spearman correlations, age- and BMI-adjusted individual linear regression, parsimonious multivariable linear regression and exploratory cluster analysis.

RESULTS

Mean (SD) FFI-D and FFI-AL were 29.8 (29.4) and 29.1 (27.7); gait velocity (GV) was 0.90 (0.34) m/s and double-support time (DS) was 22.9 (8.2)% of the gait cycle. In bivariate and age/BMI-adjusted analyses, graded structural measures showed more consistent associations with disability and gait outcomes than dichotomous/count variables. In parsimonious models, disability (FFI-D/FFI-AL) was independently associated with pain intensity (VAS) and first metatarsophalangeal joint stiffness/limited dorsiflexion (1stMTP), whereas gait performance was mainly associated with age/BMI, greater graded forefoot structural severity and 1stMTP. Cluster analysis identified a higher grey-scale synovitis (GS)/lower structural-burden group and a lower GS/higher structural-burden group, with worse function and slower gait in the latter.

CONCLUSIONS

In RA remission with metatarsal-region forefoot pain, perceived disability is mainly associated with pain and forefoot stiffness, whereas gait performance is more closely related to age/BMI and graded forefoot structural severity. These findings support severity-based region-specific structural assessment alongside pain evaluation in clinical follow-up, to avoid underestimating the independent contribution of structural damage to function and gait.