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Combination of Two Novel Nerve Blocks Reduces Opioid Use After Hip Arthroscopy

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.”


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.

About HSS

HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the 14th consecutive year), No. 2 in rheumatology by U.S. News & World Report (2023-2024), and the best pediatric orthopedic hospital in NY, NJ and CT by U.S. News & World Report “Best Children’s Hospitals” list (2023-2024). In a survey of medical professionals in more than 20 countries by Newsweek, HSS is ranked world #1 in orthopedics for a fourth consecutive year (2023). Founded in 1863, the Hospital has the lowest readmission rates in the nation for orthopedics, and among the lowest infection and complication rates. HSS was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center five consecutive times. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State, as well as in Florida. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. In addition, more than 200 HSS clinical investigators are working to improve patient outcomes through better ways to prevent, diagnose, and treat orthopedic, rheumatic and musculoskeletal diseases. The HSS Innovation Institute works to realize the potential of new drugs, therapeutics and devices. The HSS Education Institute is a trusted leader in advancing musculoskeletal knowledge and research for physicians, nurses, allied health professionals, academic trainees, and consumers in more than 165 countries. The institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally.