[Postoperative analgesic effect after intra-articular morphine or ropivacaine following knee arthroscopy - a prospective randomized, doubleblinded study]

Abstract

Introduction: Recent studies for postoperative pain relief after arthroscopy by intraarticular morphine or bupivacaine showed controversial results. The aim of the study was to evaluate the analgesic effect of intraarticular morphine and ropivacaine.

Methods: 135 patients were randomized into 9 groups (n=15) after standardized knee-arthroscopy. They received either 1 mg or 5 mg morphine or 150 mg ropivacaine or a combination of 5 mg morphine and 75 mg ropivacaine. Drains were opened either after 10 or 30 minutes. A control-group received isotonic saline. Pain was assesed 1 h and 4 h after surgery, at 8 pm on the day of the operation and at 8am and 4 pm the following two days by a VAS scale. Tramadol consumption as rescue medication was registred.

Results: Ropivacaine showed the best pain relief after surgery. After 24 h the pain intensity approximated in all groups and after 48 h there was no difference. Tramadol consumption was highest in the control group and lowest in the ropivacaine group (p<0,05). Ropivacaine showed better pain reduction than morphine. An influence of the time, when drains were opened, could only be demostrated for the 75 mg ropivacain combination group.

Conclusion: Intraarticular ropivacaine following elective knee-arthroscopy reduces postoperative analgetic consumption significantly and improves patient comfort.