Contaminated anterior cruciate ligament grafts: The efficacy of 3 sterilization agents

Purpose: A study was undertaken to determine the incidence of positive cultures resulting from an anterior cruciate ligament (ACL) specimen dropped on the operating room floor and the efficacy of sterilizing the specimen by soaking in 1 of 3 antimicrobial solutions: an antibiotic solution of neomycin and polymyxin B, 10% providone-iodine solution, and standard chlorhexidine gluconate solution. Type of Study: Randomized trial. Materials and Methods: Fifty ACL specimens removed from patients undergoing total knee arthroplasty were used as the test group. The specimens were longitudinally sectioned into 4 equal pieces. The 4 pieces were dropped on the floor and left for a period of 15 seconds. Cultures were taken from each specimen after immersion in 1 of the 3 sterilization solutions for a period of 90 seconds. One of the 4 specimens was cultured without being exposed to any solution, thereby establishing these specimens as the control group. Cultures of a floor swab were taken at the same time and place that the ACL was dropped. Results: The floor swab cultures were positive in 48 of the 50 specimens (96%). The ACL control group (untreated dropped grafts) had 29 of 50 specimens positive (58%). The grafts soaked in antibiotic solution had 3 of 50 specimens positive (6%). The grafts soaked in providone-iodine solution had 12 of 50 specimens positive (24%). The grafts soaked in chlorhexidine gluconate solution had 1 of 50 specimens positive (in broth only) (2%). Conclusion: This study shows that significant contamination occurs when dropping specimens on the floor, as 58% of the dropped grafts had positive cultures. Of the 3 sterilization techniques used, chlorhexidine gluconate seems to be the most efficient with only a single broth culture (2%) found to be positive. The antibiotic solution was second best (6%), although there is no statistically significant difference between these 2 groups. The 10% providone-iodine solution under these test conditions was the least effective of all the 3 sterilization agents with 24% cultures positive after immersion.