Patient-Related Risk Factors for Infection Following Knee Arthroscopy: An Analysis of Over 700,000 Patients from Two Large Databases

Abstract Purpose To determine patient-related risk factors for infection following knee arthroscopy using two large databases. Methods A private-payer (PP) and Medicare national insurance database were queried for patients undergoing simple knee arthroscopy procedures from 2005 to 2015. Patients undergoing concomitant open or complex procedures with grafts were excluded. Postoperative infection within 90 days postoperatively was assessed using ICD-9 and CPT codes. A multivariate binomial logistic regression analysis was utilized to evaluate patient-related risk factors, including patient demographics and comorbidities, for postoperative infection. Adjusted odds ratios (OR) and 95% confidence intervals were calculated for each risk factor, with P < 0.05 considered statistically significant. Results 100,399 patients from the PP database and 629,842 patients from the Medicare database met all inclusion and exclusion criteria. In the PP database, there were 250 patients with documented infections (0.25%); the incidence of infection was similar in the Medicare database (1755 patients, 0.28%). There were numerous patient-related comorbidities and demographics independently associated with a significantly increased risk of postoperative infection that were similar across the PP and Medicare patient populations, respectively, including younger age (OR = 1.27, 1.43), morbid obesity (OR = 1.26, 1.74), tobacco use (OR = 1.34, 1.48), inflammatory arthritis (OR = 1.61, 1.60), chronic kidney disease (OR = 1.65, 1.14), hemodialysis (OR = 1.93, 1.36), depression (OR = 2.02, 1.73), and a hypercoagulable disorder (OR = 2.76, 1.58). Conclusion The present study identified numerous patient-related risk factors independently associated with an increased risk of infection following knee arthroscopy in privately insured and Medicare-aged patients.