Biomechanical analysis of chlorhexidine power irrigation to disinfect contaminated anterior cruciate ligament grafts.

Abstract

Accidental graft contamination is a likely complication to occur in an orthopaedic sports medicine surgeon's career. There are no clinical outcome studies to direct management, and a recent survey showed that preferred management varied. Three liters of 2% chlorhexidine power irrigation has been shown to be an efficient and effective disinfection protocol; however, the biomechanical sequelae of this disinfection protocol to the graft are unknown. The purpose of this study was to determine if 3 L of 2% chlorhexidine power irrigation used to disinfect contaminated anterior cruciate ligament (ACL) grafts significantly weakens the graft at time zero. Controlled laboratory study. Eight fresh bovine superficial digital flexor tendons underwent disinfection protocol with 3 L of 2% chlorhexidine power irrigation. Contralateral tendons served as the control. Tendons were preconditioned and loaded to failure. The average ultimate failure load for the control tendons and disinfected tendons was 4081 ± 654.4 N and 4146 ± 723.2 N, respectively. The average ultimate failure stress for the control tendons and disinfected tendons was 97.10 ± 12.03 MPa and 95.18 ± 11.79 MPa, respectively. The average stiffness for the control tendons and disinfected tendons was 546.20 ± 28.16 N/mm and 539.2 ± 25.93 N/mm, respectively. The P values for ultimate failure load, ultimate failure stress, and stiffness showed no statistically significant difference between the chlorhexidine and control tendons. Disinfecting tendons with 3 L of 2% chlorhexidine power irrigation does not adversely weaken the tendon's tensile mechanical properties. Three liters of 2% chlorhexidine power irrigation can effectively disinfect a contaminated ACL graft without weakening the graft.