Vancomycin concentration in synovial fluid: direct injection into the knee vs. intravenous infusion.

The purpose of this study was to measure joint and serum levels of vancomycin following intra-articular (IA) or intravenous (IV) administration, and to compare the concentrations achieved in the joint fluid. IA vancomycin was only used to treat revision total knee arthroplasty (TKA) due to infection, while IV vancomycin was used as a prophylactic agent in primary and revision TKA. Both IA and IV vancomycin achieved therapeutic levels in the synovial fluid of the knee, but IA delivery of vancomycin resulted in peak levels that were many orders of magnitude higher, and also resulted in therapeutic serum levels. The half-life of IA-delivered vancomycin was just over three hours, and trough levels remained therapeutic in the joint and in serum for 24hours after IA injection.