Interscalene versus subacromial continuous infusion of ropivacaine after arthroscopic acromioplasty: a randomized controlled trial.

Introduction: Interscalene and subacromial infusion of local anesthetics have both been shown to be effective in alleviating pain after shoulder arthroscopy. We performed a prospective randomized clinical trial in which both methods were compared in patients after acromioplasty.

Methods: Forty patients received a subacromial (n = 20) or an interscalene (n = 20) continuous infusion of 2% ropivacaine (2 mL/h) after arthroscopic acromioplasty. Visual analog scale pain scores, additional medication requirements, and side effects were evaluated for 43 hours. The incidence of night pain was recorded.

Results: Compared with the subacromial infusion, the continuous interscalene infusion of ropivacaine in the operated-on shoulder resulted in significantly reduced visual analog scale pain scores measured during rest, and also during exercise at 8 and 12 hours after surgery. The incidence of night pain was significantly lower in the interscalene group (P = .018).

Conclusion: A continuous subacromial infusion of 0.2% ropivacaine (2 mL/h) is inferior to continuous interscalene infusion, particularly during the first 12 hours, but could be an alternative in patients with contraindications of interscalene anesthesia or when acromioplasty is performed as an outpatient procedure.