Upper limb sensorimotor function and functional performance in patients with rheumatoid arthritis

Purpose. Although sensorimotor deficits have been identified in isolated upper limb joints of patients with rheumatoid arthritis ( RA), relatively little is known about the presence or consequences of sensorimotor deficits in the upper limb as a whole. To address this, we compared sensorimotor and functional performance in multiple upper limb joints of patients with RA and healthy subjects. Methods. Global upper limb strength, proprioception ( joint position sense) and the time taken to perform 2 common functional daily activities ( dressing and eating) were estimated in 31 RA patients and 18 healthy subjects. Disability, pain and clinical disease activity were also assessed in the RA patients. Results. The RA patients were weaker ( mean difference 280N, 95% Confidence Interval 172 to 389; P <0.001), had poorer functional performance ( 6 sec, CI 8.1 - 23.9; P <0.001), hand grip strength ( 117 mmHg, CI 61 - 173; P <0.001) and proprioceptive acuity ( 28, CI 0.4 - 3.5; P <0.05) than the healthy subjects. Upper limb functional performance and disability in the RA patients were inversely associated with global upper limb ( r = -0.54 to -0.36) and hand grip strength ( r = -0.51 to -0.32) but not proprioception ( r = 0.55 - 0.11). Conclusions. Compared to healthy subjects, patients with RA had global upper limb sensorimotor deficits. Weakness contributes to poor upper limb function and disability in patients with RA, although the clinical importance of proprioception is unclear.