In a study conducted at Hospital for Special Surgery (HSS), researchers found that combined Pericapsular Nerve Group (PENG) and lateral femoral cutaneous nerve (LFCN) blocks were associated with faster discharge from the PACU, as well as a clinically significant reduction in postoperative opioid use. These findings were presented at the 2022 Spring American Society of Regional Anesthesia and Pain Medicine (ASRA) Annual Meeting.¹

Hip arthroscopy is one of the fastest growing orthopedic procedures in the United States, and despite being minimally invasive, it is a painful procedure for which analgesia can be difficult to manage. 

“Hip arthroscopy is becoming a more popular procedure performed at free standing ambulatory surgery centers (ASC). It is important to provide optimal analgesia to help combat against the over reliance on opioids for pain relief and also to facilitate discharge and patient satisfaction,” said Dr. David Kim, anesthesiologist at HSS.

A review of the literature for opioid-sparing options has not revealed a clearly superior regimen for managing pain after this surgery. 

Because ultrasound has become more common to perform nerve blocks, novel motor-sparing blocks have been introduced, such as the PENG and LFCN. When performed separately, these blocks have been shown to provide suboptimal pain relief or to cause quadriceps weakness, if a high volume of injectate spreads to the femoral nerve. Case studies have been written on combining these nerve blocks, but this is the first prospective randomized controlled trial conducted to validate this finding.

Investigators identified 1,559 patients who had elective hip arthroscopy at HSS between January 2019 to December 2020. Of that group, 268 received both a neuraxial anesthetic and a peripheral nerve block; 86 received a PENG and an LFCN block; and 26 received a PENG block, only. A control group of 112 patients received no blocks. 

The primary outcome was total opioid consumption in the PACU. Secondary outcomes included average numeric rating scale (NRS) pain scores, maximum NRS pain scores, length of PACU stay, incidence of postoperative nausea and vomiting, and admissions to the hospital for pain management. 

Patients who received both a PENG and LFCN block required significantly less opioids in the PACU (15 mg [15,15] vs 22.5 mg [15 34]). They were also discharged earlier than the control group (2.4 hours [1.8,3.4] versus 4.1 [3.5,4.9]); 2.72 hours versus 4.42 hours, p <0.001). The combined PENG/LFCN group also used less intravenous rescue opioids than the control group (0 mg [0,0] versus 0 mg [0,2], p = 0.0099), and the highest NRS pain scores showed a significant difference in the PENG/LFCN group vs control group (7 [5,8] versus 7 [6,8], p = 0.0437). The group who received the PENG block alone did not show a significant difference in opioid reduction, but was discharged from the PACU earlier than the control group (3.35 hours [2.7,4.3]versus 4.9 hours [3.8,5.7], p = 0.0023).

These results demonstrate the combined PENG and LFCN block could be an opioid-sparing method of pain relief after hip arthroscopy. “PENG combined with a lateral femoral cutaneous nerve block decreased opioid consumption, and facilitated expedient discharges,” Dr. Kim noted.

Dr. Kim concluded “Follow up research should include a prospective randomized controlled trial comparing PENG, PENG with lateral femoral cutaneous nerve block, and no blocks, with primary focus on analgesia and motor strength.”

Reference

1. David H Kim MD, Genewoo Hong MD, JD, Edward Lin MD, Sang Jo Kim MD, Jonathan Beathe MD, Douglas Wetmore MD, Stavros Memtsoudis MD PhD MBA, Jiabin Liu MD PhD. “Pericapsular Nerve Group block combined with a lateral femoral cutaneous nerve block decreases opioid consumption after hip arthroscopy: a retrospective cohort study.” Presented at: 47th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 31-April 2, 2021; Las Vegas, NV.