Chlorhexidine as the optimal disinfection method for an accidentally dropped autograft during an anterior cruciate ligament reconstruction surgery: A double-blind study.

Purpose: No consensus exists on the optimal sterilization method for contaminated grafts during anterior cruciate ligament (ACL) reconstruction surgery. This study evaluated the efficacy of single and multiple sequential disinfectants in sterilizing the contaminated graft. Methods: Thirty ACLs were harvested from 30 knees during total knee arthroplasty and sectioned into 10 semi-identical pieces (n = 300). All grafts were dropped simultaneously on the operating room floor and left for 60 s. Then, the grafts were assigned to the 10 study groups. (1) The control group used no sterilizing method, and in the other nine groups were used different sterilizing solutions: (2) 1% povidone-iodine (PI), (3) 4% chlorhexidine (CH), (4) antibiotics including vancomycin and colistin (AB), (5) thrice washings with PI, CH and AB, (6) twice washing with PI and CH, (7) twice washing with PI and AB, (8) twice washing with CH and AB, (9) once washing with normal saline, and (10) thrice washings with normal saline. A wet swab was also rubbed on the operating room floor. The researchers responsible for cultivation and culture analysis were blinded to the graft tags in the various groups. Results: Statistical comparisons of contamination rates between groups were performed using chi-square tests for categorical data, with Fisher's exact tests for pairwise comparisons. A p value of <0.05 was considered statistically significant for individual comparisons. Twenty-nine of the 30 control grafts were positive for bacterial culture, primarily for Staphylococcus epidermidis (n = 28) and Micrococcus luteus (n = 13). Eight samples in the PI group were positive for bacteria. No bacterium was isolated in the CH group. Grafts washed once and thrice with normal saline were positive for bacteria in 13 and 8 samples, respectively. Conclusion: This study found the 4% CH solution to be the most effective method for sterilizing autografts accidentally dropped on the operating room floor. Level of Evidence: NA (cadaveric, animal and basic science studies).