Study of the efficacy of coated Vicryl plus antibacterial suture in an animal model of orthopedic surgery

PURPOSE: To evaluate the efficacy in vitro and in vivo of a new antibacterial suture, polyglactin 910 suture with triclosan, compared with a traditional braided suture, polyglactin (Vicryl), in a validated animal model of orthopedic infection. Our primary goal was to compare the microbiologic effectiveness of the two sutures. The secondary goal was to evaluate histopathologic signs of an inflammatory response. METHODS: We used 20 Sprague-Dawley rats. Samples of Staphylococcus epidermidis were diluted to a 0.5 McFarland concentration (100,000 colony-forming units/mL). A surgical steel suture was placed in the spinous process of the rats, and the deep zone of the incision was contaminated bilaterally. Wounds were closed with one of the sutures. After 16 days, the animals were sacrificed, and the surgical wounds were reopened, with cultures being performed of both the zone adjacent to the implant and the deep region of the wound. We also studied the histopathologic features of the tissue adjacent to the implant. RESULTS: No clinical signs of infection were observed. The culture of the zone adjacent to the implant was positive in nine animals in the polyglactin group vs. three in the polyglactin 910 with triclosan group (p = 0.005). Culture of the deep zone of the wound was positive in ten animals in the polyglactin group vs. six in the polyglactin 910 with triclosan group (p = 0.03). We found predominant polymorphonuclear neutrophil populations in four samples in the polyglactin group vs. two in the polyglactin 910 with triclosan group. CONCLUSIONS: Under simulated conditions of severe intraoperative contamination, the antibacterial suture reduced the number of positive cultures after surgery by 66.6%. Judging from the available clinical information, its use might contribute to reducing the number of infected implants by 25.8%. Human studies are needed to determine the clinical implications of these results.