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Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Biomedical Engineering

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Teeter, Matthew G.

Abstract

Corrosion at the modular head-neck taper interface of total and hemiarthroplasty hip implants (trunnionosis) is a cause of implant failure and thus a clinical concern. Patient and device factors contributing to the occurrence of trunnionosis have been investigated in prior implant retrieval studies. The Goldberg corrosion scoring method is considered the gold standard for observing trunnionosis, but it is labour-intensive. As a result, previous studies have generally looked at under 250 implants for analysis. The purpose of this thesis was to do a large-scale analysis of trunnionosis and explore its relationship to device and patient factors and compare to previously known tends from more limited studies. Additionally, it was to develop a tool using machine learning for rapid screening of implants to identify for further study in order to reduce the labour burden associated with implant retrieval studies.

Summary for Lay Audience

Hip replacements are an increasingly common procedure for Canadians. Despite their safety and efficacy, sometimes the devices fail, requiring the patient to undergo an additional surgery and remove the original device. This accounts for ~10% of hip replacement surgeries done each year. Corrosion of the device has become an increasing reason for failure, and it is thought that corrosion is underreported. It is known that wear and corrosion of implants in the body may affect the tissue in the immediate area in a negative way and some patient factors may contribute to a more corrosive environment in the body. There is a need to study these retrieved devices to better understand potential patient factors that may contribute to increased rate of failure.

Goldberg scoring is a method used to observe corrosion at the taper interface for these devices. This method is labour-intensive and as a result, studies have generally looked at under 250 implants when studying their corrosion and the patient and device factors that may contribute to it. This thesis has done a 664-device study of implants and their corrosion and determined relationships between corrosion severity and patient and device factors and compared them to previously identified relationships in smaller studies. Additionally, it has developed a tool to distinguish no/mild corrosion from moderate/severe corrosion to allow for rapid screening of implants for further study, reducing the labour barrier for implant retrieval studies.

This thesis has provided the first large-scale study of retrieved hip arthroplasty devices and created a tool to make large-scale studies more accessible by reducing the labour required for early identification of devices with significant corrosion. The ability to conduct more large-scale studies allows for refinement of device design and identification of patients who may be at increased risk for corrosion of the taper. As hip arthroplasty surgeries continue to become more frequent, it is important to attempt to minimize their possible failure.

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

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