Total knee replacement (TKR) is known to be one of the most painful surgical procedures. Many treatments have been used post TKR: IV opioids, epidural infusions, peripheral nerve blocks. No one method has been recognised as the best one.~In this study we will compare two well established methods of pain treatment:~continuous infusion of local anesthetics + opioids into the epidural space,~patient controlled analgesia with IV Morphine.~The study design is double blind.~Patients will have a combined spinal-epidural anesthesia for the operation and then will be connected to 2 different pumps, one to the epidural catheter and one to the intravenous catheter, for the first 24 hours post-operatively.~Pain scores, total analgesic medications other than study medications, adverse reactions to study medications, complications and patient satisfaction will be followed by blinded observers and compared between groups.
The study purpose is to compare the effectiveness of different methods for post-operative pain treatment after total knee replacement.