Isokinetic ankle plantarflexion and dorsiflexion strength in patients with rheumatoid arthritis

Backgroud and objectives: In patients with rheumatoid arthritis ( RA), some muscle groups are affected in different stages of disease, especially those related to the affected joint. However, data on associations between functional performance and muscle strength in RA are few. Therefore we sought to determine whether isokinetic ankle plantarflexion ( PF) and dorsiflexion (DF) strength was affected in RA patients and to study the association between isokinetic strength and other clinical indicators of disability such as walking and stair-climbing time and disease activity in patients with RA. Methods: Thirty three patients diagnosed with RA in the chronic phase were selected from a rheumatology outpatient clinic and matched for age and gender with 33 healthy subjects. Isometric and isokinetic muscle strength was measured in DF and PF. The subjects were also evaluated through the Stanford Health Assessment Questionaire ( HAQ), walking and stair-climbing time. Cumulative and current steroid doses (CSD) were calculated. Results: No significant correlations were found between muscle strength and visual analogue scale ( VAS) scores, HAQ, ankle involvement, CSD ( p > 0.05). With respect to the isokinetic parameters, no differences have been been observed between RA and control groups ( p > 0.05). Walking and stair-climbing time increased significantly ( p < 0.05) in patients with RA. Conclusions: Ankle isokinetic muscle strength is not affected in inactive RA patients while negative effects of steroids on muscle strength were not demonstrated. Important determinators of walking ability in RA patients should be defined in future studies.