Comparison of the analgesic efficacy of periarticular infiltration and pericapsular nerve group block for total hip arthroplasty: a randomized, non-inferiority study

Background: Motor-sparing regional anesthesia modalities, such as periarticular infiltration (PAI) and pericapsular nerve group (PENG) block, have become the mainstay of multimodal approaches used during total hip arthroplasty (THA). We hypothesized that the postoperative analgesia of the PENG block was non-inferior to that of the PAI. Methods: Sixty patients were randomly allocated into two groups. The PAI group were injected with 100 mL of cocktail solution (ropivacaine 20 mL, ketorolac 2 mL, and epinephrine 1 mL mixed with normal saline) in periarticular tissues directly by the surgeon. The PENG group were injected with 30 mL of 0.5% ropivacaine in the iliopubic eminence plane by ultrasound. The primary outcome was the resting pain score 12 h after surgery, and the prespecified non-inferiority was 1. Additionally, the cumulative opioid consumption and quality of recovery were evaluated. Results: The mean difference in pain score 12 h postoperatively between the PENG and PAI groups was 0.6 [95% confidence interval (CI): -0.8 to 2.0]. The upper 95% CI exceeded the non-inferiority margin of 1 at all postoperative time points. There was no difference in opioid consumptions and quality of recovery scores. Conclusions: PENG block provided comparable analgesia with PAI following THA. It is not conclusive that PENG is inferior or non-inferior to PAI based on our study.