Self-reported walking difficulty: a sub-group for identifying differences in gait mechanics in patients with knee osteoarthritis

Date
2016
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University of Delaware
Abstract
Walking limitations in patients with knee OA are at increased risk for developing poor outcomes. Therefore, measuring walking ability in those with knee OA is important. Clinically, walking ability is measured via self-reported walking difficulty and gait speed. Measuring slow gait speed and its related interventions are well studied. In contrast, self-reported walking difficulty is not as well studied. Clinicians can use clinical guidelines that addresses gait characteristics pertaining to slow gait speed for patients with slow gait speed and self-report walking difficulty and for patients with slow gait speed without walking difficulty. However, there are no known studies that examines those who walk at a fast and functional gait speeds but self-report walking difficulty. Although this sub-group exists, as Ferrer and colleagues found 17% of their subjects with fast gait speed self-reported walking difficulty, little is known to guide clinical practice. As a result, since knee OA is the leading cause of walking difficulty, the purpose of this dissertation is to examine gait characteristics based on the presence of knee OA and self-reported walking difficulty. ☐ Methods: This cross-sectional study examines gait characteristics using self-reported walking difficulty and knee OA presence. Self-reported walking difficulty is defined based on responses ranging between somewhat difficult to unable to walk when answering the question How does your knee affect your ability to walk from the Knee Outcome Survey. Gait characteristic differences include comparisons among age and sex groups of subjects with knee OA and self-reported walking difficulty (Diff), knee OA and no walking difficulty (NoDiff), and no knee OA (Control) for knee kinetic and kinematics through motion capture and force plate, neuromuscular strategies via muscle electromyography, and limb dynamics using inertial measurement units. ☐ Results: Thirty-nine subjects, age and sex matched, participated in the study. Based on self-reported walking difficulty, the Diff group walked with smaller knee extension moment, p ≤ .05, larger knee adduction moment, p ≤ .05, larger lateral quadriceps-gastrocnemius co-contraction, p ≤ .05, larger tibial limb dynamics, p ≤ .05, and a relationships between limb dynamics and co-contraction that was different than the NoDiff group, p ≤ .05. Based on knee OA presence, the NoDiff group walked with smaller knee extension excursion, p ≤ .05, larger frontal plane knee excursion, p ≤ .05, larger quadriceps activation, p ≤ .05, and larger femoral limb dynamics than the control group, p ≤ .05. ☐ Discussion: This was the first study to examine self-perceived walking difficulty as a sub-group within knee OA. It was surprising to find that gait characteristics pertaining to knee extension (e.g., extension moment, quadriceps related activation) were different based on walking difficulty presence. This finding supported the importance of managing the quadriceps muscle in those with self-reported walking difficulty. The importance of effective quadriceps use may be further evidenced by the notable limb dynamic differences between the NoDiff and Diff group, which suggested that the Diff group used an ineffective neuromuscular strategies to stabilize the tibia. Further, for many known OA gait characteristics, no significant differences were found between the NoDiff and Control group, which may suggest that self-reported walking difficulty may account for some of known OA gait characteristics. Perhaps further examination of these gait characteristics may be beneficial for developing interventions that could combat walking difficulty.
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