Skip to main content
OpenTrials
Not Yet Recruiting

NCT Number: NCT06951477

Gut Microbiome in Orthopaedics: Revision Total Knee Arthroplasty

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.

Not Yet Recruiting

Trial opening soon.

Get Notified

Key information

Conditions

Revision Total Knee Arthroplasty Arthritis Inflammation Joint Diseases Musculoskeletal Diseases Osteoarthritis Osteoarthritis, Knee Pathologic Processes Pathological Conditions, Signs and Symptoms Rheumatic Diseases

Sex eligibility

All sexes

Study type

Observational

Primary location

University Hospital

London, Ontario, N6A5A5, Canada

Location contact

Brent Lanting, MD, MSc, FRCSC

PRINCIPAL_INVESTIGATOR

Lyndsay Somerville, PhD

CONTACT

[email protected]

519-685-8500 ext. 36645

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Scheduled to undergo a revision TKA
  • Willing and able to comply with follow-up requirements
  • Ability to provide informed consent
  • Ability to read, write, and speak English

Exclusion criteria

  • Pregnancy
  • Less than 3 months post-operation from primary surgery
  • Diagnosis of periprosthetic fracture
  • Scheduled for DAIR (debridement, antibiotics, and implant retention) revision surgery
  • Scheduled for stage 2 PJI revision

Treatment and study plan

Revision Total Knee Arthroplasty

Procedure

Study participants must be scheduled to receive a revision TKA.

Primary outcomes

  1. Gut Microbiome Composition

    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.

    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.

Secondary outcomes

  1. Inducible Displacement Measurements with Weight-Bearing Computed Tomography (WBCT)

    Time frame: WBCT exams will be performed at one timepoint prior to the study participant's revision surgery.

    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.

  2. Inflammation in the Knee Joint Based on [18F]FEPPA Standard Uptake Values (SUV)

    Time frame: PET/CT exams will be performed at one timepoint prior to the study participant's revision surgery.

    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.

Other outcomes

  1. Inducible Displacement and Microbiome Composition

    Time frame: Inducible displacement exams will be performed pre-operatively and will be compared to the gut microbiome from pre-operation to 6 weeks post-operation, and to the intra-operative joint microbiome.

    Joint and gut microbiome composition, along with inducible displacement measurements, will be assessed to determine whether alterations in the gut microbiome lead to increased within-bone implant motion.

  2. Implant Wear Volume and Within-Bone Implant Motion from Inducible Displacement Exams

    Time frame: Inducible displacement exams will be performed pre-operatively and will be compared to the amount of wear that has occurred on implants retrieved during revision surgery.

    Seated and standing WBCT exams will be performed. The bone and implant will be segmented, and a novel software (WBCT-RSA) will be used to measure implant motion between the seated and standing exams (inducible displacement). Change in implant position will be measured in millimeters as MTPM. An optical coordinate measuring machine will be used to quantitatively measure the amount of volume loss from the retrieved implant components. Inducible displacement MTPM will be compared to volume loss to determine if greater within-bone implant motion may cause greater wear of the implant component resulting in more volume loss.

  3. Metal Ion Levels and Within-Bone Implant Motion from Inducible Displacement Exams

    Time frame: Inducible displacement exams will be performed pre-operatively and will be compared to the amount of circulating metal ions pre-operation.

    Seated and standing WBCT exams will be performed. The bone and implant will be segmented, and a novel software (WBCT-RSA) will be used to measure implant motion between the seated and standing exams (inducible displacement). Change in implant position will be measured in millimeters as MTPM. Metal ion levels (cobalt, chromium, nickel, and titanium) will be measured from a blood draw prior to the revision surgery. Inducible displacement MTPM and metal ion levels will be compared to determine if greater within-bone implant motion causes greater levels of circulating metal ions.

  4. [18F]FEPPA Activity and Microbiome Composition

    Time frame: PET/CT exams will be performed pre-operatively and will be compared to the gut microbiome from pre-operation to 6 weeks post-operation, and to the intra-operative joint microbiome.

    Joint and gut microbiome composition will be compared to [18F]FEPPA activity, to assess whether alterations in the gut microbiome contribute to increased inflammation in the knee joint.

  5. [18F]FEPPA Activity and Implant Wear Volume

    Time frame: PET/CT exams will be performed pre-operatively and will be compared to the amount of wear that has occurred on implants retrieved during revision surgery.

    [18F]FEPPA activity from PET/CT will be used to detect the amount of inflammation present in the knee joint. An optical coordinate measuring machine will be used to quantitatively measure the amount of volume loss from the retrieved implant components as an indicator of wear. The relationship between volume loss and [18F]FEPPA activity will be assessed.

  6. [18F]FEPPA Activity and Metal Ion Levels

    Time frame: PET/CT exams will be performed pre-operatively and will be compared to the amount of circulating metal ions pre-operation.

    [18F]FEPPA activity from PET/CT will be used to detect the amount of inflammation present in the knee joint. Metal ion levels (cobalt, chromium, nickel, and titanium) will be measured pre-operatively and the relationship between inflammation and circulating metal ions will be assessed.

Study contacts

Contact information is provided by the study sponsor or research team.

Brent Lanting, MD, MSc, FRCSC

CONTACT

[email protected]

519-685-8500 ext. 33335

Lyndsay Somerville, PhD

CONTACT

[email protected]

519-685-8500 ext. 36645

Sponsors and collaborators

Lead sponsor

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Other

Registry information

Official study title

Gut Microbiome in Orthopaedics: Investigating the Role of Gut Microbiome Composition in Total Knee Arthroplasty Failure

Acronym: GUMBO

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Apr 30, 2025
Registry last updated
Sep 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.