Comparison between ropivacaine 1.5 mg ml(-1) plus fentanyl 2 mg ml(-1) and ropivacaine 1.5 mg ml(-1) plus clonidine 1 mg ml(-1) as analgesic solution after anterior cruciate ligament reconstruction: a randomized clinical trial.

Background: Ropivacaine is commonly used as local anesthetic for postoperative analgesia through an epidural catheter. Data show that several adjuvants influence the analgesic effect of local anesthetic potency.

Objective: The aim of the study was to compare fentanyl and clonidine as adjuvants to 1.5 mg ml(-1) ropivacaine in terms of motor blockade, pain relief and side effects.

Methods: In this single center, randomized, clinical trial, 52 patient scheduled for arthroscopic anterior cruciate ligament reconstruction were radomly allocated in two groups. At twenty-six patient a solution with ropivacaine 1.5 mg ml(-1) plus fentanyl 2 microg ml(-1) (group F) was administered through patient controlled epidural analgesia (PCEA) as postoperative analgesia and ropivacaine 1.5 mg ml(-1) plus clonidine 1 microg ml(-1) (group C) was administered at the remaining twenty-six patients. The VAS score, the Bromage scale and total solution consumption were documented and compared between the two groups for 24 hours after the end of the operation.

Results: The mean patient control consumption of the solution was higher at group C respect group F (p = 0.007). At the 8th hour after the operation we register a statistical significant difference at the mean VAS score between the two groups (p < 0.05) with clonidine group achieving a higher score. At the 8th and 12th hour clonidine group register a lower Bromage score than fentanyl group (p < 0.005 and p = 0.002).

Conclusion: Ropivacaine 1.5 mg ml(-1) plus fentanyl 2 microg ml(-1) administred through PCEA compared with ropivacaine 1.5 mg ml(-1) plus clonidine 1 microg ml(-1) h guarantee higher quality analgesia after ACL reconstruction.