Liposomal bupivacaine, a long-acting form of bupivacaine, has been found to be effective for postoperative pain control after total knee, total hip and total shoulder arthroplasty. We are conducting a randomized, controlled trial to evaluate pain control after arthroscopic rotator cuff repair in ambulatory patients, comparing standard care in the control group, with standard care plus the addition of injection of liposomal bupivacaine in the experimental group.