Intraoperative Corticosteroid Injection at the Time of Knee Arthroscopy Is Associated With Increased Postoperative Infection Rates in a Large Medicare Population.

PURPOSE: To employ a national database of Medicare patients to evaluate the association of ipsilateral intra-articular knee corticosteroid injections at the time of knee arthroscopy with the incidence of postoperative infection.

METHODS: A national Medicare insurance database was queried for patients who underwent ipsilateral intra-articular corticosteroid injection of the knee at the time of knee arthroscopy from 2005 to 2012. Patients who underwent arthroscopically assisted open procedures, those who underwent more complex arthroscopic procedures, and those for whom laterality were not coded were excluded. This study group was compared to a control cohort of patients without intraoperative steroid injections that was matched to the study group for age, gender, obesity, diabetes mellitus, and smoking status. Infection rates within 3 and 6 months postoperatively were assessed using International Classification of Diseases, 9th Revision, and Current Procedural Terminology codes.

RESULTS: The incidence of postoperative infection rates after knee arthroscopy was significantly higher at 3 months (0.66%; odds ratio [OR], 2.6; P < .0001) and 6 months (1.92%; OR, 3.6; P < .0001) in patients who underwent ipsilateral intra-articular knee steroid injection at the time of knee arthroscopy (n = 2,866) compared with matched controls without intraoperative injections (n = 170,350) at 3 months (0.25%) and 6 months (0.54%).

CONCLUSIONS: The present study demonstrates a significant increase in postoperative infection in Medicare patients who underwent ipsilateral intra-articular knee corticosteroid injections at the time of knee arthroscopy compared with a matched control group without intraoperative injection.

LEVEL OF EVIDENCE: Therapeutic Level III, retrospective comparative study.