efficacy of pericapsular nerve group block

Conditions: Acute Pain

Summary: hip fracture is a common orthpaedic problem especially in elderly population. fascia iliaca compartment block (ficb) and femoral nerve block are well-established technique as part of peri-operative multimodal analgesia for hip fractures. reviews have shown peripheral nerve blocks including ficb, femoral nerve block and 3-in-1 block could reduce both pain and opioid consumption compared with systematic analgesia. however, there are also literature suggesting that some nerves that account for the major hip joint sensory innervation are not consistently covered. as a result, a new ultrasound guided regional technique, pericapsular nerve group block (peng) was introduced in 2018. the primary aim of this study is to compare the analgesic effect of peng block and ficb in terms of pain score during post-operative period. it also compares the range of movement, quadriceps power and other parameters related to physical functions of the operated hip as secondary outcomes.

hip fracture is a common orthopaedic problem especially in elderly population. the number of hip fractures each year is expected to double from 2.2 million in 2017 to 4.5 million in 2050. it is the commonest reason for elderly to require hospitalisation and emergency operation. significant morbidities such as pulmonary embolism, pneumonia and bed sore can be resulted from immobility and pain. hip fracture also contributes to post-operative mortality at a rate about 8% at 1 month and 30% at 1 year. fascia iliaca compartment block (ficb) and femoral nerve block are well-established technique as part of peri-operative multimodal analgesia for hip fractures. cochrane review has shown peripheral nerve blocks including ficb, femoral nerve block and 3-in-1 block could reduce both pain at 30 minute and opioid consumption compared with systemic analgesia. in particular, ficb is found to be superior to opioids for pain control on movement, preoperative analgesic consumption, time to first analgesic request, and time to perform spinal anaesthesia. however, literature suggests that the obturator nerve is not consistently covered. the anterior hip capsule which contributes the major hip joint sensory innervation is supplied by femoral nerve (fn), obturator nerve (on) and accessory obturator nerve (aon). as a result, a novel ultrasound guided regional technique, pericapsular nerve group block (peng) was introduced in 2018, targeting the above 3 nerves. this is very important as the obturator nerve is also blocked with this technique. case reports showed reduction in pain scores compared with baseline 30 minutes after block placement and no clinically evident quadriceps weakness was detected.

Eligibility criteria:
inclusion criteria: * asa i-ii * age 18 or above * scheduled for hip fracture corrective surgery in queen mary hospital * chinese patients * able to provide informed oral and written consent * abbreviated mental test (amt) 7 or above exclusion criteria: * patient refusal * asa iii or above * allergy to local anaesthetics, opioids, paracetamol, nsaid including cox-2 inhibitors * operation delayed for more than 2 days on admission * pre-existing peripheral neuropathy or history of stroke * preoperative non-walker * pre-existing osteoarthritis of knee (kl grade 4) * multiple fractures (additional to hip fracture) * sepsis * impaired renal function (defined as preoperative creatinine level \>120 μmol or egfr \<50% of normal reference for their age group * patient with coagulopathy (platelet \ 1.5) * prior surgery at the inguinal or supra-inguinal area