The effects of chlorhexidine irrigation solution on contaminated bone-tendon allografts

The purpose of this study was to determine an expedient and effective metho d for disinfecting contaminated human bone-tendon allografts. The first par t of this study used beef muscle and cadaveric human tissues to determine t he most effective solution and volume to decontaminate tissues inoculated w ith four different organisms: Staphylococcus aureus, Staphylococcus epiderm idis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Of the solutions t ested (benzalkonium chloride, castile soap, castile soap followed by benzal konium chloride, triple antibiotic, chlorhexidine gluconate, and chlorhexid ine gluconate/triple antibiotic), only the 4% chlorhexidine power irrigatio n solution and 4% chlorhexidine/triple antibiotic bath completely disinfect ed all tissues. Work in part 2 revealed that a 2% chlorhexidine irrigation solution was equally effective as the 4% solutions. Part 3 of the study inv olved human Achilles tendon-calcaneus allografts. We found similar results: 3 liters of 2% chlorhexidine power irrigation solution thoroughly removed all microorganisms from the contaminated tissues. All control allografts ir rigated with normal saline solution alone revealed positive bacterial growt h for all four organisms after 72 hours' growth on sheep blood agar. Total decontamination time was 10 to 12 minutes. Two percent chlorhexidine irriga tion solution may be an effective method for decontaminating human bone-ten don allografts challenged with a polymicrobial inoculum. This method of dis infecting bone-tendon allografts is at least five times more expeditious th an methods in previously reported studies.