Difficulty with enrollment

To directly compare acute infection rates in patients undergoing total knee replacement with intraosseous regional administration or systemic intravenous administration of prophylactic antibiotics.

Subjects will be prospectively enrolled into the Intraosseous Regional Administration (IORA) group, and the investigators will use historical controls for the Systemic Intravenous Administration (SIA) group, to include a matched group of patients from 6 months prior to enrollment. SIA group will receive systemic dosing of cefazolin within one hour of the incision, which is the current standard of care. IORA group will receive intraosseous dosing after the tourniquet is inflated to 300-350mm/Hg. Cefazolin 1 gram will be given through an intraosseous cannula, placed into the medial aspect of the proximal tibia, after draping and before skin incision. The cefazolin will be administered as a bolus in 200 mL of normal saline. Incision will be made immediately after infusion. Subjects in both groups will receive routine care following the procedure. Primary outcome will be acute surgical site infection, which is defined as within 3 weeks after the surgical procedure. Secondary outcomes will include correlation of clinical comorbidities to the primary outcome, report complications, and compare surgery specific information (tourniquet time, blood loss).

Subjects with a penicillin allergy will receive a 200mg cefazolin test dose via a systemic intravenous route, which is the current standard of care. If no adverse reaction is observed, then the investigators will proceed with administration of 1g cefazolin via the intraosseus route.

Inclusion Criteria:

•primary diagnoses of osteoarthritis

Exclusion Criteria:

• history of compartment syndrome
• allergy to an antibiotic in the study
• venous stasis
• peripheral vascular disease