Early versus Late Periprosthetic Joint Infection after Total Knee Arthroplasty: Do Patient Differences Exist?

Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Little evidence exists comparing those with early versus late PJI. The purpose of the study was to determine comorbidity profile differences between patients developing early versus late PJI.There were 72,659 patients undergoing primary TKA from 2009 to 2021 who were identified from a commercial claims and encounters database. Subjects diagnosed with PJI were categorized as either 'early' (within 90 days of index procedure) or 'late' (> 2 years after index arthroplasty). Non-infected patients within these same periods served as control groups following 4:1 propensity score matching on other extraneous variables. Logistic regression analyses were performed comparing comorbidities between groups.Patients were significantly younger in the late compared to the early infection group (58.1 versus 62.4 years, P < 0.001). When compared to those with early PJI, patients who had chronic kidney disease (13.3 versus 4.1%; OR [odds ratio] 5.17, P = 0.002), malignancy (20.4 versus 10.5%; OR 2.53, P = 0.009), uncomplicated diabetes (40.8 versus 30.6%; OR 2.00, P = 0.01), rheumatoid arthritis (9.2 versus 3.3%; OR 2.66, P = 0.046), and hypertension (88.8 versus 81.6%; OR 2.17, P = 0.04) were all significant predictors of developing a late PJI.When compared to patients diagnosed with early PJI following primary TKA, the presence of chronic kidney disease, malignancy, uncomplicated diabetes, rheumatoid arthritis, and hypertension were independent risk factors for the development of late PJI. Younger patients who have these comorbidities may be targets for preoperative optimization interventions that minimize the risk of PJI.