Antibiotic Elution in Total Knee Arthroplasty

The purpose of the study is to characterize and quantify the level of antibiotics eluted from antibiotic laden cement after primary cemented total knee arthroplasty. Patients will be identified by medical record review to make sure they meet inclusion and exclusion criteria. Patients that qualify and sign consent will be randomized to 1 of 4 antibiotic cement groups which are pre-mixed tobramycin, hand-mixed tobramycin, hand mixed vancomycin, and hand-mixed tobramycin and hand mixed vancomycin. Study patients will be blinded to their study group. Intraoperative fluid from the knee prior to surgery and postoperative drain fluid from the knee postoperatively will be collected as well.