Motion analysis of the wrist joints in patients with rheumatoid arthritis

We investigated the characteristics of the wrist joint motion in patients with rheumatoid arthritis (RA), using a biaxial flexible goniometer. Wrist joint range of motion and velocity were measured on the dominant hand in RA patients (n = 22) and normal individuals (n = 5). We investigated flexion-extension (FE) task, radial-ulnar deviation (RUD) task, and functional motion tasks, such as writing letters or unscrewing the lid of a jar. In normal individuals, there was cooperative coupling of FE and RUD during wrist movement, and this coupling motion was essential for normal wrist movements. On the other hand, in RA patients, wrist joint range of motion was restricted at various degrees, with reduced joint motion velocity that was severe on RUD. Functional wrist motion tasks indicated circumductive movement with both FE and RUD in normal individuals, whereas the direction of movement was limited in RA patients, and results revealed failure of cooperative coupling of FE and RUD. Our results indicate that disturbed coupling of FE and RUD results in difficulties in the cooperative movements and have great influence on the daily activities in RA wrist joint.