Discriminant Validity and Reproducibility of Spatiotemporal and Kinetic Parameters During Treadmill Walking in Patients With Knee Osteoarthritis

Background: Instrumented treadmills are potentially useful tools for the assessment of gait parameters in orthopaedic clinical settings, but their measurement properties remain uncertain.

Research question: What 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)?

Methods: A 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).

Results: Significant 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.

Significance: We 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.

Keywords: Gait; Incline walking; Instrumented treadmill.