Discriminant validity and reproducibility of spatiotemporal and kinetic parameters during treadmill walking in patients with knee osteoarthritis

Abstract

BackgroundInstrumented treadmills are potentially useful tools for the assessment of gait parameters in orthopaedic clinical settings, but their measurement properties remain uncertain. Research questionWhat is the discriminant validity and reproducibility of spatiotemporal and kinetic gait parameters measured by a pressure-instrumented treadmill at different speeds and inclinations in patients with knee osteoarthritis (KOA)? MethodsA total of 54 patients with unilateral KOA and 23 healthy controls took part in the study. Step length, single-limb support duration and ground reaction force were recorded during level and uphill walking at 3 and 4 km/h using a commercially-available treadmill instrumented with an integrated pressure platform. We examined discriminant validity (difference between involved and uninvolved side as well as against healthy controls) and test-retest reproducibility (reliability and agreement). ResultsSignificant side differences were observed for single-limb support duration and ground reaction force at touchdown in all conditions (P < 0.05). All the investigated gait parameters showed acceptable reliability and agreement, except step length at 4 km/h uphill. SignificanceWe conclude that the pressure-instrumented treadmill used in this study may have good clinical utility for quantitative gait analysis in patients with KOA under different experimental conditions.