What is the Impact of Early Adult Rheumatoid Arthritis on the Biomechanical and Functional Characteristics of the Foot and Lower Limb?

Early rheumatoid arthritis may be characterized by the rapid onset of functional impairment. Despite advancements in the management of this disease, more than half of all patients experience significant walking impairments within the first two years following diagnosis. Clinical research has adopted 3D motion capture to provide data on musculoskeletal impairment in rheumatoid arthritis. However, there is limited published research using 3D motion capture to investigate the effects of early rheumatoid arthritis on the biomechanical function of the foot and lower limb. To translate laboratory based findings into clinical practice, more comprehensive data are therefore required in order to optimise the recognition and targeted management of early musculoskeletal pathology in rheumatoid arthritis.
Protocols were developed for the examination of lower limb walking patterns in early rheumatoid arthritis using 3D motion capture. When the walking patterns of 18 early rheumatoid arthritis participants were compared to an age and gender matched control group, significant between-group differences in spatial-temporal parameters and joint movement patterns within the foot were observed. Walking speed in early rheumatoid arthritis participants was found to be significantly slower (p<0.05). This was accompanied by a delay in terminating stance (p<0.05). Principal component analysis showed that early rheumatoid arthritis participants exhibited a significantly greater (p<0.05) magnitude of eversion and abduction of the rearfoot and midfoot during gait. A significantly reduced (p<0.05) magnitude of dorsiflexion at the first metatarsophalangeal joint was also observed. Kinematic coupling relationships between the rearfoot and midfoot were also found to be significantly altered (p<0.05), suggesting that an additional source of mechanically based trauma is also present within the foot. Linear regression analysis showed that these features were largely unexplained by current measures of disease activity and disease impact.
The findings of this research suggest that mechanically based foot pathology in early rheumatoid arthritis is of a greater magnitude than previously reported and that these changes are not explained by laboratory based measures of disease activity or patient-reported questionnaires. Based upon these findings, the multidisciplinary use of 3D motion capture is recommended to meet both current and future demands for the early assessment and targeted management of mechanically based foot pathology in early rheumatoid arthritis.