Pericapsular Nerve Group Block Leads to Small but Consistent Reductions in Pain Between 18 and 24 Hours Postoperatively in Hip Arthroscopy for Femoroacetabular Impingement Surgery: A Prospective, Randomized Controlled Clinical Trial

Purpose

This study aimed to (1) investigate whether the use of a Pericapsular Nerve Group (PENG) block would reduce peri-operative pain after arthroscopic therapy for femoroacetabular impingement syndrome (FAIS) and (2) to examine opioid requirements and occurrence of postoperative nausea and vomiting (PONV).

Methods

Between May 2022 and October 2022, patients (N = 68) undergoing arthroscopic surgery for FAIS were randomly allocated into two groups. The first group received an ultrasound-guided PENG preoperatively with 20 ml of 0.375% ropivacaine and standardized post-operative oral medication. The second group received a sham block preoperatively with 20 ml of 0.9% saline and standardized post-operative oral medication. The primary endpoint was pain scores (visual analogue score, 0 to 10) during the first 24 hours postoperatively. To quantify clinical significance of outcome achievement for the VAS pain score, the minimal clinically important difference (MCID) was calculated using the ½ standard deviation method. The incidence of post-operative nausea and vomiting as well as opioid usage (converted to morphine equivalent) within the first 24 hours were secondary outcomes.

Results

Randomization and permission were successfully obtained from 68 participants. From the fifteenth postoperative hour, the PENG group reported significantly less postoperative pain than the control group (24^th postoperative hour: VAS pain PENG group 1.3 ± 0.9 (0 – 3; 95% Confidence Interval {CI} [0.4, 1.2]) vs. VAS pain control group 2.4 ± 1.6 (0 – 5; 95% CI [1.4, 4.7]); p=0.009). The VAS pain score threshold for achieving the MCID at 24 hours postoperative was defined as a decrease of 1.1. 27 patients (79%) in the PENG group and 22 patients (65%) in the control group were able to achieve MCID (p=0.009). Opioid dosage and postoperative nausea did not differ significantly between groups (p = 0.987 and p=0.655, respectively). Concomitant complications such as falls, hematomas, or weakened muscles did not occur in either group.

Conclusion

According to this study, a PENG block minimally reduced pain after arthroscopic treatment for FAIS between the 18th and 24th postoperative hours. The PENG group achieved significantly more often the pain VAS MCID. However, there was no proof that the PENG group consumed fewer opioids than the control group. Overall, PONV was found at a low and comparable rate.