Analgesic Effectiveness of PENG Block in Programmed Hip Arthroplasty Surgery (THAPeng)

The intra- and peri-articular infiltration of local anaesthetics realized at the end of total hip arthroplasty surgeries is an effective analgesic technique, but it can be insufficient to manage the possibly intense postoperative pain. Regional anaesthesia (RA) like the recently described pericapsular nerve group (PENG) block could provide additional analgesic benefit in this setting. Investigators main objective is to demonstrate the analgesic benefits (postoperative pain score and morphine consumption) of the PENG block when added to intra- and peri-articular infiltration of local anaesthetic following total hip arthroplasty. Investigators make the assumption that i) the PENG bloc could reduce the postoperative 24 first hours morphine consumption by 30%, ii) the PENG block could spare the motor function of the quadriceps and adductor muscles, and iii) the PENG bloc could be well tolerated allowing a high level of patient satisfaction.

A recent study has revealed a region of pericapsular terminal branches of the femoral nerve and the obturator nerve accessible to ultrasound-guided regional anaesthesia. This technique, also called the PENG block, has recently been described with a substantial benefit on pain at rest and induced by mobilization in cases series of patients undergoing hip fracture surgery. To investigators knowledge, no randomized data concerning the analgesic efficacy of the PENG block has been published in the setting of elective total hip arthroplasty. The PENG block would allow a significant analgesic contribution when added to intra- and peri-articular infiltration of local anaesthetics while being well tolerated with few undesirable effects. Moreover, the PENG block could spare the motor function of the quadriceps and adductor muscles allowing enhanced recovery after surgery

For the PENG group, the ultrasound-guided PENG block (20 ml of Ropivacaine 4.75 mg/ml) is performed before the surgery.

ultrasound-guided PENG block realized before surgery. The PENG block, described by Giron-Arebgi is made in the supine position. The ultrasound probe used is a 5 MHz high frequency linear probe placed parallel to the line delimited by the anterior-inferior iliac spine (lateral) and the pubis (medial). The needle used is an 80 mm, 22G, needle inserted in the ultrasound plane. The slow and fractioned injection of 20 ml of Ropivacaine 4.75 mg/ml is performed in the fascia between the psoas tendon and the iliopubic eminence under ultrasound guidance.

Evaluation of the pain potentially induced by the realization of the PENG block with Likert scale from 1 to 5, 1 is for no pain, 5 is for the worse pain

Evaluation of the patients' satisfaction by the EVAN-LR score realized 24 hours after surgery. EVAN-LR is a scale assessing perioperative patient's satisfaction with Loco Regional anaesthesia

Evaluation of the adductor muscles weakness by a thigh adduction test performed 24 hours after surgery

Evaluation of the quadricipital muscles weakness by a Timed to Up and Go Test performed 24 hours after surgery

Inclusion Criteria: Scheduled for total hip arthroplasty surgery under general anaesthesia Affiliated of a social security scheme Having signed the written informed consent Exclusion Criteria: Total hip arthroplasty revision surgery Refusal of the patient to participate Existence of major spontaneous or acquired haemostasis disorders Infection at the puncture site Allergy to local anaesthetics Pregnancy or breast-feeding Patients under the protection of adults (guardianship, curatorship or protection of justice) Patients whose cognitive state does not allow assessment by the scales used.