The In Vitro Elution Characteristics of Vancomycin from Tendons

Abstract

Background Infection after ACL reconstruction is uncommon but catastrophic. Prophylactic graft saturation in vancomycin reportedly reduces infection rates. Questions/purposes We characterized vancomycin elution from soaked tendons. Specifically, the effect of rinsing was studied. We also determined how vancomycin concentration in the soak solution and tendon dimension influenced this elution rate, and examined whether the vancomycin amount released was lower than osteoblast and chondroblast toxic concentrations. Methods Bovine tendons were wrapped in sterile gauze swabs presoaked with 5-, 2.5-, or 1.25-mg/mL vancomycin solutions. After 10 minutes, rinsed and unrinsed tendons were placed in 100 mL agitated 37°C phosphate-buffered saline (PBS). One-milliliter samples taken at 10 minutes and 1, 6, 12, 24, and 72 hours were analyzed by highperformance liquid chromatography. ResultsThe maximum elution rate occurred between 10 minutes and 1 hour, with no lag between experiment initiation and drug appearance in the solution. Rinsing affected the initial amount in solution but had little influence on drug release after 10 minutes. Vancomycin diffusion rates were dependent on soak solution concentration at all sampling intervals. The vancomycin amount released or eluted did not increase after the 1-hour interval. At 24 hours, concentrations were 45 ± 12, 16 ± 1, and 9 ± 3 lg/mL for the 5-, 2.5-, and 1.25-mg/mL solutions, respectively. Higher elution rates were observed in largervolume tendons. Conclusions Soaked tendon grafts can act as reservoirs for vancomycin, with the amount released and elution profile dependent on rinsing, tendon volume, and soak solution concentration. Vancomycin elution was lower than previously reported osteoblast and chondroblast toxicity concentrations and above the minimum inhibitory concentration for Staphylococcus. Clinical Relevance Presoaking ACL reconstruction autografts with vancomycin may reduce the risk of ACL reconstruction infection without the risk of local or general toxicity.

Vancomycin-soaked autografts during ACL reconstruction reduce the risk of post-operative infection without affecting return to sport or knee function

“…The protocols of vancomycin autograft presoaking are very similar in all the published studies. All of these studies were based on the protocol described by Grayson et al [7]. In our study, the transplant was soaked in a dish containing a vancomycin solution for 10 min and then placed and fixed in the bone tunnel without rinsing.…”

No infections in 1300 anterior cruciate ligament reconstructions with vancomycin pre-soaking of hamstring grafts

“…Vancomycin is less toxic than other alternative antibiotics, such as Tobramycin, Cefazolin, and Gentamicin, with levels above 125 micrograms/mL required before osteoblastic toxicity occurs and bone regeneration is inhibited [1]. An antibiotic concentration of at least 2 micrograms/mL is required for effective eradication of the Staphylococcal species, creating a wide therapeutic window to avoid toxicity to local tissues [14].…”

Managing septic arthritis after knee ligament reconstruction

“…With regard to new prophylactic measures described to decrease infection rate following ACLR, recent investigations demonstrated that presoaking the autograft in a diluted solution of vancomycin is effective for this purpose [24][25][26]. Other measures, such as the use of gentamicin irrigation solution, have been shown as less effective [27].…”