Pericapsular Nerve Group Block for Hip Fractures

Isolated hip fractures are common and are associated with significant morbidity and mortality.1 2 The American Academy of Orthopedics provides strong evidence for peripheral nerve blocks as a safe, effective method to manage perioperative analgesia. Literature shows that peripheral nerve blocks decrease the need for opioids and its deleterious effects including respiratory depression and delirium, and can provide superior pain control when compared to parenteral analgesia.2-10 In addition to significant pain, patients with isolated hip fractures are at risk for underassessment of pain and subject to considerable delays in analgesic administration even after their pain is identified, in one study the average delay to treatment was 122 minutes.11

Ultrasound guidance has been shown to be a safe method for performing a peripheral nerve block.12 Overall, peripheral nerve blocks are a safe procedure with rare complications of nerve injury or local anesthetic toxicity.12,13

While the femoral nerve block, the "3-in-1" block, and the fascia iliaca block are popular analgesic approaches to hip fractures, they have their downsides. Literature suggests that these blocks provide inconsistent and partial analgesia.2,15, 16 A possible explanation is demonstrated by both MRI and cadaver studies that illustrate that the obturator nerve (sensory innervation) is rarely affected by these three blocks and can cause motor weakness. The potential benefit of a pericapsular nerve group (PENG) block is that its effect is sensory, while preserving motor function.

The target of the PENG block, the anterior zone of the hip, contains the highest relative concentration of sensory fibers to the hip. This part of the labrum is innervated by articular branches of the femoral nerve (FN), accessory obturator nerve (AON) and obturator nerve (ON).2 17-20 The PENG block is a novel approach described by Giron-Arango et al in 2018 as an ultrasound guided technique to target the FN, AON, and ON.2 By targeting the articular branches of these three nerves as they course between the anterior inferior iliac spine and the iliopubic eminence (IPE), the PENG block is able to provide a sensory-only blockade without causing motor weakness.2 21-23 Currently, there are case series/reports showing that the PENG block is highly efficacious for pain.

Aim/Objectives:

We intend to conduct a feasibility study among 10 emergency department (ED) patients with hip fractures to determine logistical barriers to introducing a new procedure in an ED as well as to assessing pain and efficacy of the PENG block.

Study Design:

This study will take place in the Jacobi Adult ED. This will be a 10-patient prospective, observational, feasibility study regarding the PENG block for hip fractures in adults. The emergency physician (EP) will identify 10 cognitively intact patients with hip fractures in the ED. The EP has the option to provide a standard dose of intravenous narcotics during the initial assessment if clinically warranted until radiographic confirmation of a fracture. Once a fracture has been confirmed, the research team will be contacted. The patient will be enrolled into the study if they had a pain score greater than or equal to 5/10 at triage or upon initial EP evaluation before the intravenous analgesia, if there was no pre-hospital analgesia given, and if there are no concomitant injuries. To be included into the study, the patient will be alert, oriented to person, place, and time, and must be able to demonstrate understanding of the written consent form. Patient also has to be able to indicate how much pain they are in using a visual analog pain scale, with 0 being no pain and 10 being severe pain, and be able to report any side effects experienced after administration of the nerve blockade. If the patient refuses to be in the study, it will not hinder the patient from obtaining other avenues of pain management and all other care. The pain score assessed just before the nerve block will be considered time 0. The blocks will be performed with dynamic sonographic guidance using a Sonosite X-porte machine and the curvilinear transducer using sterile technique. EP were trained on the PENG block after a workshop series consisting on a lecture and three hands- on training using a low-fidelity model. Competency was determined once the participant successfully performed the block on the low-fidelity model without intervention by the trainer. They also had to pass a three part check list, including taking consent and verbalizing aseptic technique, and scoring > 90% on a multiple choice quiz. Patients are eligible to receive standardized rescue doses of intravenous narcotics after the PENG block if they experience continued pain. Pain scores will be assessed for 16 hours at pre-determined points.

Inclusion criteria

• >18 years old (male or female)
• cognitive intact patients with Isolated hip fractures (both surgical and non-surgical candidates)
• displaced/non-displaced displaced/non-displaced sub-trochanteric
• displaced/non-displaced intra-trochanteric
• displaced/non-displaced femoral neck/head fractures

Exclusion criteria

• patient refusal
• allergy to local anesthetic
• overlying infection at injection site
• patients who cannot provide consent.