Rebound pain after arthroscopic cuff repair with interscalene brachial plexus block anesthesia is reduced by surgeon administered multimodal shoulder injections: A prospective randomized controlled trial.

Purpose: To compare the effects of additional multimodal shoulder injections on postoperative rebound pain in patients undergoing arthroscopic rotator cuff repair (ASRCR) under interscalene brachial plexus block (ISBPB) anesthesia.

Methods: A single-blind randomized controlled trial was conducted with 67 patients between April 2023 and December 2023. Patients undergoing ASRCR got an ISBPB anesthesia, not general anesthesia, were included with a minimum follow-up period of 48 h. The injection group received 40 mL of 0.75% ropivacaine, 20 mg morphine, 1:200,000 epinephrine, and saline solution, totaling 100 mL. Following surgery, the injection was administered to the subacromial space (50 ml) with blind suprascapular nerve block (25 ml) and blind axillary nerve block (25 ml). Controls received 100 mL of saline solution. Intravenous patient-controlled analgesia (IV-PCA) was used as adjuvant analgesia for all patients. The primary outcome was evaluated using the visual analog scale (VAS) pain score at 12 h after surgery, with secondary outcomes of the incidence of rebound pain and VAS pain scores at 0, 2, 4, 8, 24, 36, and 48 h postoperatively. Fentanyl in IV-PCA and rescue analgesic amounts, complications, and satisfaction were recorded.

Results: Sixty-seven patients (32 in the injection group, 35 in the control group) with a mean age of 61.1±9.0 years were included. The primary outcome assessment, VAS pain score at 12 h, significantly favored the injection group (2.7±0.93 vs. 4.1±1.70, p<0.001). The incidence of rebound pain was 18.8% and 65.7% in the injection and control groups, respectively (18.8% vs 65.7%, p<0.001). The injection group reported better VAS pain scores at 24, 36, and 48 h, and lower fentanyl use over the 48 h postoperative period (p=0.014). The use of rescue analgesics was similar between groups and no complications were associated with multimodal shoulder injections. Satisfaction levels were similar in both groups.

Conclusion: The present study found that multimodal shoulder injections during ASRCR under ISBPB anesthesia significantly lowered VAS pain scores at 12 hours postoperatively and reduced the incidence of rebound pain compared to the control group. Pain levels were consistently lower from 12 to 48 hours postoperatively. Additionally, the injection group had reduced opioid consumption within the first 48 hours postoperatively, with no complications observed.

Level of evidence: Level I, randomized controlled trial.