Physical Activity and the Role of Walking in Knee Osteoarthritis

Abstract

Walking is recommended as a type of physical activity for individuals with knee osteoarthritis, yet this population is physically inactive. The quantitative effects of walking exercise on joint health to inform walking prescription remain poorly understood. The overall aim of this thesis was to better understand whether and how physical activity, particularly walking, is prescribed to manage knee osteoarthritis, and to add to our understanding of the effects of walking on quantitative joint health outcomes for individuals with knee osteoarthritis. A healthcare quality survey of individuals with mild-to-moderate knee osteoarthritis (Chapter 3) revealed that less than half of participants received recommended care across four healthcare quality indicators, and approximately two-thirds received advice to exercise. Binary logistic regressions indicated no differences in healthcare quality based on participant demographic, social, or patient-reported factors. Within a systematic review and meta-analysis on the biomechanical and structural effects of walking interventions (Chapter 4), pooled data analysis from 33 articles indicated walking interventions elicit minimal-to-no change in discrete biomechanical metrics of joint loading, and moderately increase gait speed. Longer interventions were associated with lower peak knee flexion moments in meta-regressions. Descriptive analyses suggested walking exercise does not alter knee joint structure beyond natural history changes. A laboratory-based experimental study on the immediate biomechanical, structural, and patient-reported effects of a 30-minute walking bout (Chapter 5) indicated that continuous walking increases peak knee joint loading, elicits minimal-to-no increases in pain, and does not change cartilage thickness. Pain and structural imaging responder and non-responder sub-groups were identified and examined in exploratory analyses. Low exercise prescription rates (Chapter 3) are unsurprising given the little quantitative evidence that currently exists to support walking exercise (Chapter 4); however, the effect of walking exercise on biomechanical, structural, and patient-reported outcomes (Chapters 4 and 5) support that more individuals with knee osteoarthritis should be advised to exercise. This thesis adds to growing evidence that exists to educate patients on the potential overall and joint health benefits of walking exercise, and absence of harms related to disease progression. Findings can be used to inform walking prescription parameters to increase physical activity for knee osteoarthritis populations.