Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Kinesiology

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Thornton, Jane S.

Affiliation

International Olympic Committee

2nd Supervisor

Pamukoff, Derek N.

Abstract

Post-traumatic osteoarthritis (PTOA) occurs in most individuals after severe knee injuries such as anterior cruciate ligament (ACL) ruptures, leading to significant pain, symptoms, functional limitations, and reduced quality of life. A deeper understanding of the mechanisms that drive PTOA progression after knee injury is essential to develop effective treatment and prevention strategies. The purpose of this thesis was to investigate the influence of joint loading on PTOA development and the clinical characteristics of individuals with PTOA.

Chapter 2 is a systematic review that compared physical activity levels of individuals with ACL reconstruction (ACLR) to international guidelines and to those of uninjured controls. Individuals with ACLR achieved recommended moderate-to-vigorous physical activity levels, but not daily steps, and were less physically active than uninjured controls. Therefore, individuals with ACLR may obtain additional knee health benefits by increasing daily steps, and they should be advised by clinicians to stay active in safe and feasible ways to optimize their long-term knee health.

Chapter 3 investigated between-limb differences in gait biomechanics and cartilage morphology and associations between these outcomes at seven years after ACLR. Gait biomechanics were symmetric, but cartilage thickness and composition differed between limbs with certain regions showing signs of compromised morphology. There were multiple associations between gait biomechanics and cartilage outcomes. These results demonstrated potential degenerative cartilage changes at seven years after ACLR that may be influenced by gait biomechanics.

Chapter 4 compared clinical characteristics between individuals with knee OA with and without previous PTOA-associated injuries. Individuals with PTOA-associated injuries had superior physical and psychological health outcomes and higher physical activity levels than those without PTOA-associated injuries. Thus, individuals with PTOA have unique clinical characteristics and may require interventions with less emphasis on physical activity behaviours than those with non-traumatic osteoarthritis.

Overall, our findings suggest that joint loading may influence PTOA outcomes after severe knee injuries and that individuals with PTOA may benefit from different clinical management strategies than those with non-traumatic osteoarthritis. This thesis provides a strong basis for further investigation of the biomechanical mechanisms potentially driving PTOA development and exploration of tailored interventions for the PTOA population.

Summary for Lay Audience

Severe knee injuries lead to knee osteoarthritis (OA) development in most cases. It is important to investigate how quantitative and qualitative aspects of joint loading are related to knee OA development after injury to better understand the mechanisms that drive degenerative processes in the knee joint. Additionally, understanding the unique characteristics of individuals with knee OA related to injury will help guide the development of tailored treatments for this specific type of OA.

Chapter 2 reviewed the available evidence regarding physical activity levels after knee surgery. The results of the study suggest that individuals typically meet global physical activity guidelines after surgery, but they may obtain additional health benefits from walking more.

Chapter 3 examined walking movement patterns, magnetic resonance imaging measures of cartilage structure, and relationships between these outcomes at seven years after knee surgery. While individuals demonstrated symmetric walking movement patterns, cartilage structure differed between legs and showed potential early indicators of degeneration. Walking movement patterns were also related to cartilage structure and may play a role in knee OA development seven years after surgery.

Chapter 4 compared characteristics between patients with knee OA with versus without previous severe knee injuries. Compared to those without previous knee injuries, those with previous knee injuries were younger, more physically active, and had better physical and psychological health. Therefore, while physical activity should be promoted to all individuals with knee OA to optimize their health, it may be more effective for those without previous knee injuries since they are less active.

Together, these results demonstrate that joint loading plays an important role in knee OA development after severe knee injuries, and those with previous knee injuries have characteristics that are distinct from than those without previous knee injuries suggesting they may benefit from different treatments.

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