Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Doctor of Philosophy

Program

Electrical and Computer Engineering

Supervisor

Teeter, Matthew G.

2nd Supervisor

McIsaac, Kenneth A.

Joint Supervisor

Abstract

Prevalence of osteoarthritis is increasing as individuals are remaining active later in life. Since the knee is one of the most commonly affected joints and is involved in almost all daily activities, functional impairment has a substantial impact on overall health. Despite this increase, there currently exists no disease modifying drugs or treatments. Mild cases are managed with physiotherapeutic exercises and common anti-inflammatories but surgical intervention is required for more severe disease progression.

Total knee replacement as a treatment for osteoarthritis is a highly successful surgery that is effective at restoring knee function and reducing pain but still requires further refinement. Over 70,000 of these surgeries are performed annually in Canada with 99% for the treatment of degenerative arthritis. Despite improvements to surgical technique and implant designs, studies report up to 20% of patients remain dissatisfied with their knee replacement up to the point of not undergoing the surgery again if it were an option. A singular cause for this dissatisfaction has not been pinpointed but strong influencers are pain, low functional improvement, and unmet expectations.

Early detection of functional problems permits further intervention through targeted physiotherapy or additional surgeries before problems escalate and cause patient dissatisfaction or implant revision. Current methods of patient evaluation rely on self-reported measures, which suffer from ceiling and floor effects often masking inter-patient differences. These measures are also influenced from patient expectations and what a patient reports they "can'' do, is not always representative of their true functional ability.

Wearable sensors permit objective functional measurement of the knee as a supplement to patient-reported measures. Instrumented performance tests can measure patient function and compare to similar recoveries to highlight deficiencies or positive recovery traits. This thesis outlines the development of such a wearable system for in-clinic measurement and the extraction of functional parameters to predict future outcomes and give surgeons the earliest indications for intervention. This information can also help surgeons realistically adjust patient expectations for recovery, even before undergoing surgery. It is expected that these individualized assessments to set expectations before surgical intervention will help address the persistently high patient dissatisfaction.

Summary for Lay Audience

Total knee replacement is a commonly performed surgery where the knee is replaced by an artificial joint. In Canada, 99% of these surgeries are performed as a treatment to knee osteoarthritis (OA): a disease that causes breakdown of cartilage, pain, and loss of joint function. Although exercise and medications are often prescribed for mild cases, this currently remains the only treatment available for late-stage knee OA.

Unfortunately given total joint replacement is the only solution to restore function and improve the quality of life of affected patients, up to one in five patients self-reports they are dissatisfied with their surgery and many indicating they would not undergo it again if it were an option. A variety of reasons for this dissatisfaction have been uncovered such as persisting pain, low joint function improvement, and expectations of how a new knee would perform not being met.

When undergoing knee replacement, evaluation tools to measure patients and track the joint recovery are limited. Complex equipment is not accessible for many clinics and physical space restrictions limit equipment that can be used. Questionnaires which instruct patients to self-report their abilities, pain, expectations, and satisfaction are most commonly used to get patient feedback. Unfortunately these can be unreliable when patients cannot distinguish subtle changes in their own health. Furthermore, perceived impairments could be caused by other joints (such as the hip) or conditions external to the knee which may unfairly influence answers.

The work presented in this thesis focuses on the development of a knee measurement tool that can be used in the clinic by patients and surgeons to get instant feedback on knee function. These measurements will be free of patient or surgeon bias, which permits results to be compared to previous visits or other patients. Later work describes the use of these measurements to predict how much function a patient may regain even before their surgery, which can help the surgeon set realistic expectations for the patient, which in turn, is expected to help manage patient satisfaction.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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