70 patients scheduled for major orthopaedic shoulder surgery were randomized to receive a postoperative interscalene block with ropivacaine, administered as either intermittent boluses every 2 hours or continuous infusion. Patients were assessed for pain scores, morphine use and consumption, PCA boluses administered and attempted, and adverse effects over the first 48 hours after surgery. Pain scores, morphine consumption, and PCA boluses administered and attempted did not significantly differ between the two groups. The incidence of specific adverse effects, including hoarseness and reduced cough strength, were significantly greater among patients administered intermittent boluses.