Doctor of Philosophy
Health and Rehabilitation Sciences
Musculoskeletal Health Research
Birmingham, Trevor B.
Knee osteoarthritis (OA) is a progressive degenerative condition that can affect all tissues within the joint. Methods to measure early changes in joint structures and the effect of interventions are required. The purpose of this thesis was to investigate aspects of quantitative magnetic resonance imaging (MRI) as outcome measures in knee OA studies. Specifically, changes in articular cartilage composition and/or effusion-synovitis were examined in people with or at risk for knee OA and healthy controls, and after altering joint loads.
Chapter 2 is a systematic review that studied articular cartilage composition using MRI T2 and T1ρ relaxation in patients at risk for knee OA and healthy controls. We performed meta-analyses to examine the effect of knee OA risk factors on T2 and T1ρ relaxation. The presence of risk factors resulted in lengthened T2 and T1ρ relaxation. These findings support the use of compositional MRI to detect articular cartilage degeneration early in the OA disease process.
Chapter 3 explores the acute response of knee articular cartilage T2 relaxation to a functional loading stimulus in patients at risk for knee OA and healthy controls. T2 relaxation shortened similarly in both groups following the loading stimulus. The loading stimulus evoked consistent changes in articular cartilage composition but did not detect compromised articular cartilage in patients at risk for knee OA.
Chapter 4 evaluates the effect of high tibial osteotomy (HTO), a limb realignment surgery, on T2 relaxation of articular cartilage in patients with knee OA and varus alignment. Shortening of T2 relaxation was observed in the medial compartment, with no change in the lateral or patellar compartments, suggesting HTO can improve articular cartilage composition in the targeted compartment, without harming other compartments.
Chapter 5 studies the effect of knee load on effusion-synovitis, using HTO as a model. The change in knee adduction impulse was associated with the change in effusion-synovitis. The findings suggest that mechano-inflammation is an active pathway in knee OA that can respond to biomechanical intervention.
Overall, this thesis provides evidence that quantitative MRI is sensitive to structural changes of articular cartilage and effusion-synovitis at various stages of knee OA.
Summary for Lay Audience
Knee osteoarthritis (OA) is a chronic disease that affects the entire joint. Changes throughout the joint contribute to knee OA. Being able to measure change is important to understanding how the joint responds, and which treatments are effective. Quantitative magnetic resonance imaging (MRI) measures specific changes within the knee joint. This thesis uses quantitative MRI to measure changes in articular cartilage and inflammation in knee OA.
Chapter 2 measures how the makeup of articular cartilage differs between patients at risk for knee OA and healthy participants in previously published studies. After evaluating all of the literature, people at risk for knee OA had unfavourable changes in their cartilage compared to healthy controls, well before being diagnosed with OA.
Chapter 3 studies how articular cartilage responds to knee joint load in patients at risk for knee OA and healthy controls. After both groups completed a challenging workout, the cartilage of both groups responded very similarly. This suggests that people at risk for knee OA still have similar cartilage function despite being at greater risk for knee OA.
Chapter 4 evaluates the effect of surgical realignment of the lower limb on the makeup of articular cartilage in patients with knee OA with bowed legs and pain on the inside of the knee. One year after surgery, articular cartilage structure was improved on the inside of the knee, with no changes to the outside of the knee or under the kneecap. This shows that surgical realignment can help the cartilage of patients with knee OA.
Chapter 5 evaluates long term changes in joint load on inflammation within the joint, using surgical realignment as the method to induce changes in joint load. One year after surgery, patients who experienced the greatest reductions in load during walking had substantial decreases in inflammation within the knee joint. This shows that joint load is a major contributor to inflammation, and is treatable by changing the load.
All of these findings were determined using quantitative MRI, an extremely valuable tool to determine how the joint changes over the course of disease, and how it responds to treatment.
Atkinson, Hayden F., "Quantitative Magnetic Resonance Imaging of Knee Articular Cartilage and Effusion-Synovitis: The Structural Response to Changes in Joint Loading" (2020). Electronic Thesis and Dissertation Repository. 7253.
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