Does IVPCA Increase Opioid Consumption and Side Effects in Fast Track Orthopedic Procedures?

Inclusion Criteria: * Male or female patients aged 18 to 80 years old * Provision of written informed consent * Patients scheduled to undergo primary knee surgery included in the fast track protocol under regional anesthesia only * Patients with Body Mass Index (BMI) between 18 to 34.9 * Patients with American Society of Anesthesiologists (ASA) physical status classification of 1 to 3 Exclusion Criteria: * Patients on chronic (more than twice a week) opioid treatment including Tylenol #3, percocet, morphine, methadone, hydromorphone, fentanyl patch and other potent opioids * Patients with language barrier or difficulty in communication in English * Patients who are allergic to morphine and hydromorphone, fentanyl, gabapentin, celecoxib or acetaminophen * Patients with increased risk for respiratory depression with intrathecal morphine (OSA, central apnea) * Patients with documented Renal or hepatic impairment