Inter-Limb Asymmetry in Motion: Combining Clinical and Biomechanical Outcomes to Understand its Prevalence and Responsiveness in Knee Osteoarthritis

Abstract

Walking is consistently recommended for individuals with knee osteoarthritis; however, many avoid physical activity due to pain. Individuals with knee osteoarthritis may attempt to alleviate this pain by adopting asymmetrical walking patterns, which potentially increases the risk for osteoarthritis progression in their contralateral knee. Unfortunately, inter-limb asymmetry in knee osteoarthritis is understudied and not well understood. The overall aim of this thesis was to investigate inter-limb asymmetry quantified using features of dynamic knee joint loading previously associated with knee osteoarthritis onset and progression, and examine its clinical utility based on its relationships with clinical and structural characteristics of knee osteoarthritis and responsiveness to physical activity.

A comparison between individuals with self-reported versus clinically diagnosed knee osteoarthritis revealed that individuals with self-reported knee osteoarthritis walked with gait patterns associated with more severe knee osteoarthritis compared to individuals who are clinically diagnosed (Chapter 4). Regardless of recruitment method, approximately 50% of individuals with knee osteoarthritis walked with asymmetrical knee loading (Chapter 4). Dichotomizing individuals with knee osteoarthritis with either symmetrical or asymmetrical knee loading revealed that individuals with symmetrical knee loading had worse patient-reported function (Chapter 5). Individuals with symmetrical knee loading walked with contralateral knee biomechanics consistent with knee osteoarthritis and in individuals with asymmetrical knee their contralateral knee biomechanics were consistent with asymptomatic individuals (Chapter 5). Walking 30-minutes was not found to negatively influence objective function in individuals with symmetrical or asymmetrical knee loading (Chapter 6). However, pain increased two-fold in individuals with symmetrical versus asymmetrical knee loading after walking 30-minutes (Chapter 6). Inter-limb symmetry-asymmetry status was consistent following 30-minutes of walking regardless of baseline status (Chapter 6).

These studies suggest that approximately half of individuals with knee osteoarthritis walk with asymmetrical knee loading. Contrary to previous thoughts, symmetrical knee loading may be an indicator for bilateral gait patterns resembling knee osteoarthritis in this population. Despite increases in pain, inter-limb symmetry-asymmetry status was consistent following 30-minutes of walking. Clinically, a symmetry-asymmetry index may hold utility as a screening tool to assess potential knee osteoarthritis severity or monitor responsiveness to interventions; however, further research assessing more clinically applicable tools are warranted.