31 patients (62 knees) scheduled for simultaneous bilateral total knee arthroplasty were randomized to undergo the procedure with or without the addition of morphine to periarticular injection with ropivacaine, epinephrine, keotprofen, and methylprednisolone. The purpose of this study was to determine if the addition of periarticular morphine was associated with significantly decreased postoperative pain, greater range of motion, and lower severity of thigh swelling. Results demonstrated that all pain outcomes, functional outcomes and thigh swelling/circumference measurements were comparable between patient knees.