Patient-controlled epidural analgesia versus continuous epidural analgesia after total knee arthroplasty.

Patient-controlled epidural analgesia (PCEA) has been found to be an effective method for pain relief during labour and after surgery. The goal of this study was to compare the efficacy of bupivacaine-fentanyl PCEA and continuous epidural infusion with the same mixture for treatment of pain after total knee arthroplasty.Fifty-four patients under spinal anaesthesia were allocated to two groups in this randomized, double-blind study: the PCEA group could demand a bolus of 0.05 ml/kg of the bupivacaine 1.1 mg/ml and fentanyl 5 microg/ml solution, with a lockout interval of 10 min and total dose limit of three bolus doses per hour. The EPI group received a continuous infusion of 0.1 ml kg(-1) h(-1) of the same bupivacaine-fentanyl solution, and only a minimal extra bolus dose of 0.2 ml with the same lockout interval. All the patients received also paracetamol 1 g, orally, three times a day. In addition to pain scores at rest and during leg lifting, the 20-h analgesic consumption and the incidence of side effects were recorded.Forty-nine patients completed the study. The bupivacaine and fentanyl consumption during 20 h was smaller in the PCEA group (P<0.001). Analgesia and the need for rescue-opioid medication were similar in both groups. There were no differences between the PCEA and EPI groups regarding the incidence of side effects. Five patients were confused about how to operate the PCEA apparatus.The amount of bupivacaine-fentanyl solution consumed was significantly less with PCEA than with continuous infusion of bupivacaine-fentanyl solution without affecting the quality of postoperative analgesia after total knee arthroplasty. Several of the elderly patients had difficulties in operating the PCEA apparatus.