The purpose of this study is to determine whether or not giving a lower dose of antibiotics (Vancomycin) in the area where it is needed (the knee joint) is more effective at preventing infection than the current standard dose which is given intravenously (IV) through a wrist vein.

Patients were assigned to one of two groups by chance (like a coin toss):

• GROUP 1 - Received 500mg of vancomycin into the tibia (shin) bone of the leg being operated on.
• GROUP 2 - Received 1g of vancomycin, which is the amount normally given to patients.

For both groups, the revision knee replacement will then be carried out as normal.

OTHER ANTIBIOTICS All patients received cefazolin IV (an antibiotic used to prevent infection) prior to the beginning of surgery to ensure effective preventive antibiotics. The patient will also received 3 postoperative doses of cefazolin over a 24-hour period (4 doses in total). This is standard of care for all total knee replacement surgeries.

TISSUE SAMPLES

• Ten (10) tissue samples were taken during the surgery, consisting of both bone and fat beneath the skin. Each sample were very small, around the size of a pinhead.
• In addition, a drain sample was taken from the knee joint drain fluid to measure vancomycin concentration the morning following surgery.
• These samples were frozen and sent to a lab for analysis.

Inclusion Criteria:

• Revision total knee arthroplasty
• Informed consent given

Exclusion Criteria:

• Current treatment with IV Vancomycin within the preceding 7 days
• Previous hypersensitivity to vancomycin
• Significant cardiac or respiratory abnormality
• Contraindications to using the intraosseous vascular access system (EZ-IO)
• Sepsis

Although 22 subjects were enrolled, 2 subjects were withdrawn from the study following an intra-operative decision not to proceed with a full revision. Baseline demographics are provided for the subjects who completed the study.