Background Juvenile idiopathic arthritis (JIA) encompasses a complex group of disorders with arthritis as a common feature. Patients with JIA may experience significant disability owing to muscular weakness, joint pain, contracture, and reduced mobility. Stair climbing performance is frequently used as a measure of lower extremity funtions in patients with chronic disease.

Objectives The aim of this study was to investigating the factors affecting stair climbing in patients who have an affected knee joint with oligoarticular JIA.

Methods 30 patients (aged 6–18 years) who have an affected knee joint with oligoarticular JIA were included in this study. Active range of motion (AROM) of knee was evaluated with universal goniometer. Muscular strength was estimated at maximal isometric force for the muscles of the lower extremities by using a portable handheld dynamometer (Lafayette, LA). Postural balance control was evaluated by using the Flamingo Balance Test (FBT). Static balance was measured by using the Functional Reach Test (FRT). Stair climbing performance was assessed with 10-stair climbing test (10SCT). All tests were performed thrice and the mean values of all were recorded. Relations between the factors affecting stair climbing in JIA were assessed by multiple linear regression analysis.

Results The mean age was 9.63±2.76 and the mean disease duration was 4.41±2.16 years. Significant relationships were found between 10SCT and hip flexion muscle strength (r=-0.45 p=0.013), hip external rotation muscle strength (r=-0.48 p=0.007), knee extension muscle strength (r=-0.45 p=0.015) and dorsiflexion muscle strength (r=-0.37 p=0.044). According to linear regression analysis, stair climbing performance was affected by only hip flexion muscle strength (β=-0.40 p=0.026). However, it was not found relationships between AROM, FRT, FBT and 10SCT (p>0.05).

Conclusions Stair climbing is a biomechanically complex activity of daily life for children. In current study, it was found that stair climbing performance was related with lower extremity muscle strengths in patients with JIA. Althought patients with JIA had only one affected knee joint, hip flexion muscle strength was primary predictor of stair climbing performance. We suggested that stair climbing performance should be considered in patients with juvenile idiopathic arthritis. Thus, not only affected joint, but also all lower extremity joints should be assessed multidimensionally.

Disclosure of Interest None declared