Continuous epidural analgesia with bupivacaine-fentanyl versus patient-controlled analgesia with i.v. morphine for postoperative pain relief after knee ligament surgery.

BACKGROUND: Both epidural analgesia and intravenous patient-controlled analgesia (PCA) have been found efficacious after various types of surgery. We compared the efficacy, safety, side effects and patient satisfaction of these methods in a randomized double-blind fashion after elective anterior cruciate ligament reconstruction of the knee.

METHODS: Fifty-six patients had an epidural catheter placed at the L2-L3 interspace. Spinal anaesthesia with 15 mg of plain bupivacaine 5 mg/ml was performed at the L3-L4 interspace. After surgery the patients were randomly divided into three groups: 19 received a continuous epidural infusion with bupivacaine 1 mg/ml and fentanyl 10 mg/ml (F10), 19 patients received bupivacaine 1 mg/ml and fentanyl 5 microg/ml (F5) and 18 patients received saline (S). The rate of the epidural infusions was 0.1 ml kg(-1) h(-1). Each patient could also use an intravenous (i.v.) PCA device with 40 microg/kg bolus doses of morphine with a lockout period of 10 min and a maximum dose 240 microg kg(-1) h(-1). At the end of surgery ketoprofen 100 mg i.v. was given and continued orally three times a day. Patients were assessed for pain with a visual analogue scale (VAS) at rest and during activity, side effects and satisfaction at 3, 9 and 20 h.

RESULTS: Both epidural infusions (F10, F5) provided better analgesia than epidural saline plus i.v. PCA (S) (P<0.05). There was slightly less nausea in the S group (NS). In spite of the difference in the quality of pain relief, there was no difference between the groups in patient satisfaction regarding analgesic therapy.

CONCLUSION: Epidural infusion of fentanyl (1 microg kg(-1) h(-1) or 0.5 microg kg(-1) h(-1)) and bupivacaine (0.1 mg kg(-1) h(-1)) provided better pain relief but more side effects than intravenous morphine patient-controlled analgesia after knee ligament surgery. Almost all patients in all groups were satisfied with their pain relief.