Comparison of femoral triangle plus iPACK blocks with femoral triangle block alone for anterior cruciate ligament reconstruction: a randomized controlled clinical trial on postoperative pain and knee function.

Background: Anterior cruciate ligament reconstruction (ACLR) can cause severe postoperative pain. However, consensus regarding the most effective regional analgesia is lacking. We hypothesized that, compared with femoral triangle block (FTB) and local infiltration analgesia, adding an iPACK block would decrease postoperative morphine consumption.

Methods: Patients scheduled for ACLR under general anesthesia were randomly allocated to the FTB (n=45) or the FTB+iPACK group (n=45). The primary outcome was the cumulative oral morphine equivalent (OME) consumption during the first two postoperative days. Secondary outcomes were maximum pain scores, opioid adverse effects, and knee functional scores (Knee Injury and Osteoarthritis Outcome (KOOS), International Knee Documentation Committee (IKDC) and Lysholm) 3, 6, and 9 months after surgery.

Results: Compared with FTB, FTB+iPACK resulted in similar OME consumption (median (IQR)=50 (14-103) vs 60 (32-89) mg, respectively; median of the difference (95% CI): 5 (-14, 28) mg, p=0.49). No significant intergroup differences were found in terms of pain scores, opioid-related side effects, or functional knee recovery. Pain and symptoms subscales of KOOS and IKDC at 9 months were higher for patients with an OME consumption <50 mg within the first two postoperative days, but these statistical differences did not reach the minimal clinically important difference.

Conclusions: iPACK block has no additional analgesic benefits for primary ACLR in the setting of a multimodal analgesia regimen including FTB and local infiltration analgesia.

Trial registration number: NCT05136352.