This is a randomized, placebo controlled, single blind study of intravenous (IV) acetaminophen in a postoperative arthroscopy patient population. Although use of this medication as a non-narcotic analgesia has been validated in other patient populations such as post operative pelvic and abdominal surgeries, it has not been demonstrated in those who have recently undergone knee arthroscopy with or without chondroplasty. In this study all participants will be injected with a standard of care intra-articular dose of ropivacaine HCl, .2% (Naropin) prior to transfer to the Post Anesthesia Care Unit (PACU). Each will be randomized 1:1 to receive IV acetaminophen in 100ml of 0.9% NS (treatment group) or a 100 ml 0.9 % NS placebo (control).