Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Health and Rehabilitation Sciences

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Marsh, Jacquelyn D.

2nd Supervisor

Birmingham, Trevor B.

Co-Supervisor

Abstract

Purpose: To evaluate the effectiveness of two distinct interventions in improving outcomes for patients with knee osteoarthritis (OA) and varus alignment: 1) a 12-week minimally supervised therapeutic exercise program with nutrition recommendations, 2) and high tibial osteotomy (HTO).

Methods: This dissertation involved four studies. Participants were recruited as part of two separate ongoing prospective cohort studies evaluating clinical, biomechanical, and physiological outcomes following a) a 12-week exercise and nutrition program (studies 1-2) or b) HTO (studies 3-4) for knee OA. For studies 1 & 2, we evaluated change in physiological measures (body composition, muscle strength, gait biomechanics), patient-reported measures (pain, function, quality of life, perceived exertion) and performance-based measures, and explored associations among variables. For studies 3 & 4, we evaluated responder criteria at 2 years after HTO, the rate of conversion from HTO to total knee replacement (TKR), and changes in patient-reported outcomes and gait biomechanics at 2, 5 and 10 years after HTO. We also evaluated associations between demographics and biomechanics with various clinical outcomes (i.e., responder criteria, TKR, clinically important improvements in patient-reported outcomes).

Results: For the exercise and nutrition program, patients worked harder while experiencing decreases in exercise-induced pain. Patients also experienced substantial improvements in physiological measures (body composition, muscle strength, gait speed), and patient-reported and performance-based outcomes. While physiological measures were associated with patient-reported and performance-based outcomes, magnitudes of association were small.

Following HTO, 78% of patients were responders to surgery at 2 years. There were also 5% of patients who went on to a TKR at 5 years, and 20% at 10 years after HTO. Substantial improvements in pain and function, and reductions in knee joint moments (i.e., >40%) were also maintained up to 10 years post-HTO. Changes in gait biomechanics were associated future TKR and meaningful improvements in pain and function.

Conclusions: We showed a therapeutic exercise and nutrition program similar to everyday physical therapy practice can be effective in improving various patient outcomes. We also showed HTO leads to substantial long-term improvements and may delay the need for TKR, suggesting HTO may provide an opportunity for secondary prevention of OA.

Summary for Lay Audience

Knee osteoarthritis is common and affects over 500 million people around the world. It can lead to severe pain, poor function, and worse quality of life. We need to find ways to improve treatments to help patients feel better and get them participating in everyday activities. The purpose of this thesis was to study the effectiveness of 1) a nutrition and exercise program (similar to physiotherapy), and 2) high tibial osteotomy (HTO), a surgery aimed at correcting varus alignment (i.e., bowed legs), with the goal of helping patients feel better and reducing risk of their OA getting worse.

For the nutrition and exercise program, we evaluated changes in body composition, strength, and walking mechanics, and asked patients about their pain, function, quality of life, and how hard they believed to be working while exercising. We also wanted to see if these different measures were related to each other to figure out ways to optimize benefits from similar nutrition and exercise programs in the future. We showed participants were able to work harder over the 12 weeks while experiencing reductions (instead of increases) in knee pain caused by exercise. Participants also got leaner, stronger, and walked faster, while also feeling better, improving daily function and overall quality of life. However, exercise and nutrition led to minimal changes in knee joint loading.

Higher knee joint loads are common in knee osteoarthritis and can increase risk of osteoarthritis becoming worse over time. HTO surgery helps reduce these knee loads, but we are unsure how long benefits last. We evaluated how many patients had large improvements in knee pain and function (i.e., responded) at 2 years after HTO surgery, how many got a knee replacement over 10+ years, and whether symptom benefits and knee load changes last up to 10 years. We found 78% of patients responded to surgery at 2 years, 80% did not get a knee replacement at 10 years, and patients continued to feel good while maintaining reduced knee loading at 10 years. We also showed the amount of load reduction from surgery can affect risk of future knee replacement.

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Available for download on Saturday, August 31, 2024

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