Gut Microbiome in Orthopaedics

Overview

Patients having knee replacement surgery regularly experience joint pain and compromised bone quality leading to implant loosening and periprosthetic fractures. The role of the gut microbiome, which is the collection of bacteria and other microbes within the human gastrointestinal tract, is just beginning to be recognized, including its potential effects on pain, infection, and loosening after total joint replacement. Antibiotics are regularly used in orthopaedic surgery to reduce the risk of infection, but they also harm gut microbiota and reduce their potentially beneficial effects. Probiotics may have a role to play in enhancing bone quality and decreasing synovial inflammation after joint replacement surgery, and this study will explore the potential relationship of probiotic use with implant migration, bone density, and patient outcomes. This study is a randomized, controlled, double-blinded trial comparing probiotic use with placebo in post-menopausal women undergoing primary total knee replacement. The main questions it aims to answer are: * to compare implant migration between groups from baseline to six weeks post-surgery * to compare bone density and joint inflammation between groups from baseline to six weeks post-surgery * to compare gut microbiome composition and patient-reported outcome measures between groups from baseline to six weeks post-surgery

Participants will take a daily probiotic (DE111®) or placebo once daily starting 3 weeks prior to surgery until six weeks after surgery. The following will be completed at baseline and 6 weeks: * Bloodwork * Fecal sample collection * MRSA swab * Patient-reported outcome measures * CT imaging scan In addition, the following will be done: * Intraoperative fluid and tissue collection * Positron Emission Tomography-Magnetic Resonance Imaging (PET-MRI) scan at 6 weeks post-surgery Researchers will compare the probiotic and placebo groups for any significant differences in implant stability, bone quality, inflammation, gut microbiome composition, and pain.