Spatiotemporal gait symmetry in individuals with clinical unilateral knee osteoarthritis compared to healthy controls: A pilot study

Abstract

<p><strong>Purpose: </strong>This study describes gait characteristics and evaluates whether step length, step time and stance time symmetry index (SI) ratio (differences between limbs divided by the bilateral average) and variables of each limb (limb-specific) can be reliably measured in a sample of unilateral knee osteoarthritis (KOA) and healthy participants. A secondary objective estimates between- and within-group differences and correlations between SIs and limb-specific variables with measures of pain, perceived exertion and physical function over an experimental walking intervention.</p> <p><strong>Design: </strong>Observational cohort. SI and limb-specific variables test-retest reliability and differences in KOA and healthy individuals before and after the walk intervention were estimated.<strong> </strong></p> <p><strong>Methods: </strong>Eight subjects were in each of the KOA and healthy groups. The GAITRite® captured step length, step time and stance time on three test occasions. Test-retest reliability was measured over two administrations. Pain (Numeric Pain Rating Scale) and perceived exertion (Borg Rating of Perceived Exertion) were collected before and after each test. The six-minute and treadmill walk tests comprised the experimental walking intervention. Point and interval estimates of SIs and limb-specific variables before and after the walk intervention for test-retest reliability, between- and within-group differences as well as Pearson correlations were obtained.</p> <p><strong>Results: </strong>Limb-specific variables showed better test-retest reliability (ICC 0.94 to 0.97) than SIs (ICC 0.77 to 0.87). Differences were observed in both groups’ perceived exertion rating (KOA -7.4 (-8.5 to -6.4); Healthy -6.7 (-8.0 to -5.5)) over the experimental walking intervention. In the KOA group, high correlations (r = 0.75 to 0.93) were observed between pain and both step and stance times as well as physical function and step length, varying in magnitude and direction depending on which limb was supporting.</p> <p><strong>Conclusion: </strong>The findings suggest that limb-specific measures are reliable and useful as biomechanical indices of compensatory KOA gait, correlating with pain and physical function.</p>