Pain severity reduction in subjects with knee osteoarthritis decreases motor-cognitive dual-task costs

Abstract

BackgroundPain has disruptive effects on cognitive functions leading to a decreased capability to multi task. This might be the reason why pain is a fall risk factor in dual-task situations. This study aims to relate a decrease/increase in pain severity with a decrease/increase in dual-task costs of gait variability, which is associated with fall risk, in patients with osteoarthritis prior to and 6–8weeks after total knee replacement. MethodsWe assessed the variability of minimum toe clearance in normal walking and dual-task walking in 36 patients (14 male and 22 female participants; age=mean 64.4, SD (9.2) years) with knee osteoarthritis one day before total knee replacement and again 6–8weeks after the operation. We assessed pain severity with the Brief Pain Inventory. Dual-task costs were calculated as the percentage change of gait variability from single-task walking to dual-task walking. We subtracted the post-test values from the pre-test values of both outcomes to get absolute changes. We calculated the correlation using Kendall's Tau. FindingsSubjects with a high difference of pain severity were more likely to have higher differences of dual-task costs of gait variability (rτ=0.416, p=0.000). InterpretationOur data suggest that a reduction of pain severity goes along with a reduction in dual-task costs. This indicates that pain might have substantial influence on fall risk in daily-life multi-task situations due to its detrimental effects on cognitive processes which may be adequately addressable by interventions that alleviate pain.