Effects of Continuous Nerve Block vs Single Injection Block With PCA vs PCA on Pain and Function After Knee Replacement

Inclusion Criteria: * 40 years and above * Osteoarthritis * Primary unilateral total knee replacement * No other lower extremity joint disease * ASA I-III * Body mass index \< 35 * No severe cardiac or pulmonary diseases * No chronic narcotic therapy or illicit drug use * Mentally competent to understand study procedures and use of pain scales * Able to provide informed consent Exclusion Criteria: * Any cause for knee replacement other than osteoarthritis * Total knee revision * Any contraindication for femoral block * Abnormal coagulation studies * Thrombocytopenia less than 100,000/cc * Known hepatic or renal insufficiency * Neurological disease involving lower extremities * Major surgery during the last 2 weeks pre-operatively * History of allergy to study medications * History of post-operative bleeding over 2000 cc/24 hours * History of opioid or alcohol abuse * Currently taking or has taken opioid \> 30 consecutive days of daily use at a daily dose \> 15mg morphine, within the past 2 weeks prior to surgery * Previously has not responded to opioid analgesics for treatment of pain * Pregnancy or breastfeeding