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

Introduction. Recent studies for postoperative pain relief after arthroscop y by intraarticular morphine or bupivacaine showed controversial results. T he 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 standardiz ed knee-arthroscopy. They received either 1 mg or 5 mg morphine or 150 mg r opivacaine or a combination of 5 mg morphine and 75 mg ropivacaine. Drains were opened either after 10 or 30 minutes. A control-group received isotoni c 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. T ramadol 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 d ifference. Tramadol consumption was highest in the control group and lowest in the ropivacaine group (p<0,05). Ropivacaine showed better pain reductio n than morphine. An influence of the time, when drains were opened, could o nly be demostrated for the 75 mg ropivacain combination group. Conclusion. Intraarticular ropivacaine following elective knee-arthroscopy reduces postoperative analgetic consumption significantly and improves pati ent comfort.