80 patients undergoing elective or trauma shoulder surgery were randomized to an interscalene brachial plexus block with either ropivacaine plus tramadol or ropivacaine plus saline. Patients were primarily assessed for pain severity and morphine consumption over the first 24 hours after surgery. Results demonstrated that, while pain scores and morphine consumption from 2 hours to 8 hours did not significantly differ between groups, both pain score and morphine consumption at 24 hours was significantly lower in the tramadol group compared to the control group.