Total knee arthroplasty can cause severe postoperative pain, and patients typically receive oral opioid analgesics for over 2 weeks. Side effects of pain management may impair participation in physical therapy and diminish patient satisfaction. Anecdotally, it seems that pregabalin is very helpful to patients after total knee arthroplasty. However, pregabalin can have side effects. It is not clear how much pregabalin to prescribe. Low doses may not be effective, but use of high doses may increase the incidence and severity of side effects.The purpose of this study is to determine which dosage of pregabalin is the most effective at reducing pain after knee surgery.