This is a prospective, randomized control trial designed to compare the effects of using the short-term and long-term combination ON-Q nerve blocks in connection with TKA surgery. The ON-Q nerve block and pump system provides slowly infused, continuous delivery of a local anesthetic to the surgical site and nerves. The use of concurrent saphenous and posterior knee nerve blocks with the ON-Q system has been adopted as standard procedure at our institute. The study does not involve an alteration to the typical procedures currently being employed. Ultrasound will ensure the accuracy of catheter placement by a regional anesthesiologist.