Graft Preparation with Intraoperative Vancomycin Decreases Infection after Anterior Cruciate Ligament Reconstruction: A Review of 1640 Cases

OBJECTIVES: Septic arthritis is a rare but devastating complication following anterior cruciate ligament (ACL) reconstruction. Reported infection rates following ACL reconstruction are low, but associated with high morbidity including reoperation and inferior clinical outcomes. The purpose of the current study was to investigate the rate of infection after ACL reconstruction with and without graft preparation with vancomycin irrigant. METHODS: All ACL reconstructions performed from May 2009-August 2018 at a single, large academic institution were reviewed and categorized based on vancomycin use. Those with <90-day follow-up, intraoperative graft preparation with an antibiotic other than vancomycin, or previous ipsilateral knee infection were excluded. Infection was defined as a return to the operating room for irrigation and debridement within 90 days of ACL reconstruction. Descriptive and inferential statistical analysis using t-tests and Poisson regression were performed, with statistical significance defined as p<0.05. RESULTS: In total, 1,640 patients (952 males; 58.0%) with a mean age of 27.7 + 11.4 years underwent ACL reconstruction (1,379 primary procedures; 84.1%) and were included for analysis. Intraoperative vancomycin was used in 798 cases (48.7%) while 842 ACL reconstructions (51.3%) were performed without intraoperative vancomycin. There were eleven total infections (0.7%), with ten infections occurring in patients without vancomycin-soaked grafts (1.2%) and one infection occurring in grafts soaked in vancomycin (0.1%; p=0.008). Age (p=0.571), gender (p=0.707), smoking (p=0.407), surgeon (p=0.124), and insurance type (p=0.616) were not associated with postoperative infection. There was an 89.5% relative risk reduction with the use of intraoperative vancomycin. Increased body mass index (BMI) (p=0.029), increased operative time (p=0.001), and absence of ACL graft preparation with vancomycin (p=0.032) independently predicted postoperative infection. CONCLUSION: The use of vancomycin-soaked grafts was associated with a ten-fold reduction in postoperative infection after ACL reconstruction (0.1% versus 1.2%; p=0.032). Other risk factors for postoperative infection after ACL reconstruction included increased BMI and increased operative time.