DOS 2018

DOS Kongressen 2018 · 199 Penetration of Vancomycin to Infected Bone Implant Cavities – Evaluation in a Porcine Model Mats Bue, Pelle Hanberg, Janne Koch, Louise Kruse, Martin Lundorff, Bent Aalbæk, Henrik Elvang Jensen, Kjeld Søballe, Mikkel Tøttrup Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Experimental Medicine, University of Copenhagen; Department of Veterinary Disease Biology, University of Copenhagen; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Randers Regional Hospital Background: The increasing incidence of orthopaedic methicillin- resistant Staphylococcus aureus (MRSA) infections represents a significant therapeutic challenge. Being effective against MRSA, the role of vancomycin may become more important in the orthopaedic setting in the years to come. Purpose / Aim of Study: To evaluate the effect of implant-associated osteo- myelitis on vancomycin bone penetration. Materials and Methods: In eight pigs, implant-associated osteomyelitis was induced on day 0, using a Staphylococcus aureus strain. Following administra- tion of 1,000 mg of vancomycin on day 5, vancomycin concentrations were obtained with microdialysis for 8 hours in the implant bone cavity, in cancellous bone adjacent to the implant cavity, in subcutaneous adipose tissue (SCT) ad- jacent to the implant cavity, and in healthy cancellous bone and healthy SCT in the contralateral leg. Venous blood samples were also obtained. The extent of infection and inflammation was evaluated by post-mortem computed tomog- raphy scans and a histological evaluation of the peri-implant pathological bone area (PIBA). Findings / Results: In relation to all the implant cavities, bone destruction was found. Ranging from 0.20 to 0.74, tissue penetration, was incomplete for all compartments except for healthy SCT. The lowest tissue penetration was found in the implant cavity. By a PIBA width of 3 mm, the vancomycin penetration decreased dramatically. Conclusions: Staphylococcus aureus implant-associated osteomyelitis was found to reduce vancomycin bone penetration, especially in the implant cavity. A strong negative correlation between PIBA width and vancomycin penetra- tion were found. These findings suggest that it may be unsafe to rely solely on vancomycin therapy when treating acute osteomyelitis. Particularly when me- taphyseal cavities are present, surgical debridement seems necessary. 140.