Sixty-seven patients undergoing arthroscopic rotator cuff repair were randomized to receive either multimodal shoulder injections (n=32) or placebo saline injections (n=35). The primary outcome of interest was visual analog scale (VAS) pain score at 12 hours postoperatively. Secondary outcomes of interest included incidence of rebound pain, VAS pain scores at multiple postoperative time points (0, 2, 4, 8, 24, 36, and 48 hours), fentanyl use in IV-PCA, use of rescue analgesics, complications, and patient satisfaction. Outcomes were assessed up to 48 hours postoperatively. Overall, the results of the study revealed significantly lower pain scores at 12 hours in the injection group (p<0.001) and a markedly reduced incidence of rebound pain (18.8% vs. 65.7%, p<0.001). The injection group also required less fentanyl (p=0.014), with no differences in rescue analgesic use or complications. These findings suggest that multimodal shoulder injection is a safe and effective approach to minimizing rebound pain and opioid use following arthroscopic shoulder surgery.