Antibiotic prophylaxis prior to colonoscopy with biopsy does not decrease risk of prosthetic joint infection in total knee arthroplasty recipients

Introduction: Prosthetic joint infection (PJI) risk continues to receive much attention given its associated morbidity and costs to patients and healthcare systems. It has been hypothesized that invasive colonoscopies may increase the risk of PJI. However, the decision to administer antibiotic prophylaxis lacks clinical guidance. In this study we aimed to compare PJI rates in patients undergoing colonoscopies with and without antibiotic prophylaxis against a control group, analyzing PJI occurrences at 90 days, 6 months, 9 months, and 1 -year postprocedure and (2) assess the impact of antibiotic prophylaxis on PJI rates to inform clinical guidelines. Methods: We queried a national, all -payer database to identify all primary total knee arthroplasty procedures without prior history of PJI between January 2010 and October 2020 (n = 1.9 million). All patients who had a diagnosis of PJI within one year of index procedure were excluded. There were three cohorts identified: colonoscopy with biopsy without antibiotic prophylaxis; colonoscopy with biopsy with antibiotic prophylaxis; and a control of no prior colonoscopy. Both colonoscopy cohorts were slightly younger and had higher comorbidities than the controls. The PJI diagnoses were identified at four separate time intervals within one-year after colonoscopy: 90 -days; 6 -months; 9 -months; and 1 -year. Chi-square analyses with odds ratios (ORs) and 95% confidence intervals were conducted for PJI rates between groups at all time -points. Results: Among all cohorts, no significant differences in PJI rates were found at 90 -days (P = 0.459), 6 -months (P = 0.608), 9 -months (P = 0.598), and 1 -year (P = 0.330). Similarly, direct comparison of both colonoscopy groups, with and without antibiotic prophylaxis, demonstrated no PJI rate differences at 90 -day (P = 0.540), 6months (P = 0.812), 9 -months (P = 0.958), and 1 -year (P = 0.207). Ranges of ORs between the colonoscopy cohorts were 1.07-1.43. Conclusion: Invasive colonoscopy does not increase the risk of PJI in patients who have pre-existing knee implants. Furthermore, antibiotic prophylaxis may not be warranted in patients undergoing colonoscopy who have a planned biopsy.