Many patients who receive knee replacement surgery must return for a revision (or repeat) surgery due to ongoing pain, stiffness, infection, or implant loosening. The role of the gut microbiome-the collection of bacteria and other microbes within the human gastrointestinal tract-is just beginning to be recognized in orthopaedics. The gut microbiome has been found to affect the immune response and bone regulation, potentially contributing to infection or loosening after total joint replacement. Antibiotics are regularly used in orthopaedic surgery to reduce the risk of infection, yet they might also harm gut microbiota and reduce their potentially beneficial effects. As a result, understanding the relationship between gut microbiota and surgical outcomes has become increasingly important. Therefore, this study aims to determine if there are differences in gut microbiota composition between patients with well-functioning knee replacements and those requiring revision knee replacements. Additional study aims include assessing inflammation, implant loosening, metal ion levels, and circulating bacteria in blood or tissue between well-functioning or failed knee replacements.
Study Type
OBSERVATIONAL
Enrollment
30
Study participants must be scheduled to receive a revision TKA.
University Hospital
London, Ontario, Canada
Gut Microbiome Composition
The gut microbiome composition of the revision total knee arthroplasty (TKA) cohort prior to revision surgery will be compared to that of the well-functioning TKA cohort. Additionally, we will evaluate changes in the gut microbiome within the revision cohort from before surgery to six weeks after surgery.
Time frame: Gut microbiome composition will be assessed pre-operatively and at 5 days and 6 weeks post-operation to determine how it changes post-operation.
Inducible Displacement Measurements with Weight-Bearing Computed Tomography (WBCT)
Seated and standing WBCT exams will be performed. The bone and implant will be segmented, and a novel software (WBCT-based radiostereometric analysis (WBCT-RSA)) will be used to measure implant motion between the double seated exams (precision) or seated and standing exams (inducible displacement). Change in implant position will be measured in millimeters as maximum total point motion (MTPM). MTPM will be compared between the revision TKA cohort and a cohort with well-functioning implants.
Time frame: WBCT exams will be performed at one timepoint prior to the study participant's revision surgery.
Inflammation in the Knee Joint Based on [18F]FEPPA Standard Uptake Values (SUV)
Positron Emission Tomography/Computed Tomography (PET/CT) of the knee joint will be performed using the radiotracer \[18F\]FEPPA, which binds to molecules highly expressed on inflammatory cells. Radiotracer uptake will be quantified using SUV. SUV near the bone and joint will be calculated and compared between the revision TKA cohort and the well-functioning TKA cohort.
Time frame: PET/CT exams will be performed at one timepoint prior to the study participant's revision surgery.
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