Retention of kinematic patterns during a 6-minute walk test in people with knee osteoarthritis.

BACKGROUND: Knee osteoarthritis (OA) is a chronic condition affecting the entire joint and surrounding tissue, resulting in pain, stiffness and impaired movement. Recent studies have suggested the use of physical performance tests, such as the six-minute walk test (6MWT) to assess joint function for those with knee OA. This study assessed lower limb sagittal plane joint angles during a 6MWT for people with mild-moderate knee OA.

METHODS: Thirty-one participants (18 male, 13 female; 62.9 ± 8.4 years) with knee OA were recruited. Gait data were collected in a single session during which participants completed a 6MWT around a 20 m course. Sagittal plane joint angles for the hip, knee and ankle were calculated during the first and last minute of the 6MWT. Statistical parametric mapping (SPM) was used to investigate changes in kinematic traces over the gait cycle.

RESULTS: Mean joint angles for the hip and knee showed no significant differences between the first and last minute of the 6MWT. Ankle joint kinematic traces indicated there to be a decrease in plantarflexion approaching toe-off in the last minute of the test - a 1.5° reduction from the first minute. No significant differences were calculated for walking speed or joint range of motion.

DISCUSSION: The lack of significant change in joint kinematic parameters and walking speed suggests the relative fatigue and pain burden to the participant over the duration of the 6-minute period is insufficient to elicit any mechanical changes to walking gait.