Gait patterns in subjects with rheumatoid arthritis cannot be explained by reduced speed alone

The aim of this study was to investigate the characteristics of gait in subjects with rheumatoid arthritis (RA) by comparing gait parameters obtained from these subjects and controls. Seventeen subjects with RA in functional class II (mean age 51.1 years, S.D. 6.2 years) and 20 controls (mean age 50.4 years, S.D. 5.3 years) were instructed to walk a straight walkway at five different self-selected speeds. Speed-dependent variables were analysed by an interpolation procedure to estimate scores at a normalized speed of 0.8m/s. At self-selected speed the RA group walked significantly slower, with a shorter step length and longer stance phase. There was no difference in cadence and step width. When controlling for speed, the RA group walked with shorter step length (p=0.04) and higher cadence (p=0.03) compared to controls, but no significant difference in stand phase and step width was found. The present study demonstrates that speed-dependent gait variables are affected when controlling for the effect of speed in subjects with RA. In further studies of gait, speed should be controlled for.