Cementless Triathlon 5YR Follow-Up

Study Overview
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Brief Summary
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All artificial joint implants need to be solidly held (fixed) within the bone. Cementless fixation has become a popular method to achieve fixation for total knee replacements where the bone grows directly onto the implanted device instead of using bone cement. The primary purpose of this study is to assess long-term implant survivorship and clinical outcomes of a previous study cohort that received a cementless knee replacement. As this study cohort approaches 5 years post-operation, the investigators will re-examine the stability of participant implants using specialized x-rays, called radiostereometric analysis. The study will use weight-bearing computed tomography (CT) to measure bone density and texture features and correlate that with implant stability. The investigators will collect stool samples to assess participant gut microbiomes for biomarkers of poor bone quality that could correlate to implant stability. All 33 participants from the original study cohort will be invited to participate in this study.

Official Title
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5 Year Follow-Up of Migration of a Cementless Total Knee Replacement

Conditions
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Knee Arthroplasty, Total, Knee Osteoarthritis, Radiostereometric Analysis

Intervention / Treatment
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* Device: Cementless Total Knee Replacement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Were in the originally investigated cohort Had successful imaging at 1-year post-operation Minimum of 5 years post-operation Exclusion Criteria: Pregnancy Unable to follow-up

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Prior Cementless Knee Replacement Cohort<br>Patients who received a cementless knee replacement in 2017-2018 and participated in a prior study measuring the first year of implant migration. | Device: Cementless Total Knee Replacement<br>* Artificial knee implant inserted by cementless fixation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant Migration (tibial component) | Implant movement will be measured with model-based Radiostereometric Analysis (RSA) by registering the location of the tibial component during supine exams. Potential tibial component migration between 1 and 5 years post-operation will be measured in millimeters with the use of tibial bone markers. | 5 year follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant Migration (femoral component) | Implant movement will be measured with model-based Radiostereometric Analysis (RSA) by registering the location of the femoral component during supine exams. Potential femoral component migration between 1 and 5 years post-operation will be measured in millimeters with the use of femoral bone markers. | 5 year follow-up | 
| Inducible Displacement (RSA-based) | Model-based Radiostereometric Analysis (RSA) will be used to register the location of the tibial and femoral components during supine and standing exams. Change in implant position will be measured in millimeters as maximum total point motion (MTPM) between the standing and supine RSA exams. | 5 year follow-up | 
| Inducible Displacement (CT-based) | Weight-bearing computed tomography (CT) will be used to register the location of the tibial and femoral components during seated and standing exams. Change in implant position will be measured in millimeters as maximum total point motion (MTPM) between the seated and standing CT exams. | 5 year follow-up | 
| Bone Density | Weight-bearing computed tomography (CT) scans will be used to measure bone density as Hounsfield units in standardized volumes of interest below the pegs and keel of the tibial component. | 5 year follow-up | 
| Texture Features | Weight-bearing computed tomography (CT) texture analysis will be performed in standardized volumes of interest below the pegs and keel of the tibial component. | 5 year follow-up | 
| Microbial Diversity | Participants will provide a stool sample. Microbial DNA will be extracted from the stool samples for 16s rRNA sequencing. Taxonomy will be assigned and functional annotation will be determined. | 5 year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Osteoarthritis, Cementless Fixation, Gut Microbiome, Weight-Bearing Computed Tomography