The PENG Block in Elective Hip Surgery and Its Effect on Postoperative Pain and Length of Stay.

The PENG Block in Elective Hip Surgery and Its Effect on Postoperative Pain and Length of Stay: A Multidisciplinary Prospective Randomized Double-blind Controlled Trial.

Effective postoperative pain management in elective hip surgery is crucial for the patients well-being, rapid mobilisation and potential reduction of length of stay. In addition to standard intravenous pain medication, anaesthetic blocks are reportedly effective. Recently, the PENG block, a pericapsular pain block without impairment of the motor function has been introduced in literature and performed at the investigator's hospital (HFR Fribourg, Switzerland) for total hip arthroplasty and surgical hip dislocation - the two most commonly performed elective hip surgeries. As high-quality evidence on the effectiveness of this novel block is lacking, the investigator's objective is to evaluate the effectiveness of (1) patient-reported pain reduction, (2) total consumption of postoperative morphine, and the length of stay at the hospital.

Forty patients undergoing total hip arthroplasty and 40 patients undergoing surgical hip dislocation will be enrolled in a prospective, double-blind, controlled trial performed at the investigator's hospital. This study will be the first prospective study evaluating the potential of this pain block in elective hip surgery potentially affecting both patients' postoperative well-being and optimizing costs of the hospital by reducing length of stay.

PENG block, Postoperative pain, Elective hip surgery, Total hip arthroplasty, Surgical hip dislocation

Interdisciplinary, prospective, double-blind (participant and investigator), placebo-controlled, parallel-group study (experimental study, level of evidence I).

All patients will undergo the same preoperative, standardized protocol. Upon arrival to the operating theatre, routine, standard pre-medication will be applied before induction of general anesthesia. After intubation, the PENG block is performed. Under sonographic guidance, 20 mL of 0.5% ropivacaine iv is injected.

All patients will undergo the same preoperative, standardized protocol. Upon arrival to the operating theatre, routine, standard pre-medication will be applied before induction of general anesthesia. After intubation, the PENG block is performed. Under sonographic guidance, 20 mL of NaCL 0.9% is injected.

All patients will undergo the same preoperative, standardized protocol. Upon arrival to the operating room, patients will be placed in supine position. Routine, standard pre-medication will be applied before induction of general anesthesia. After intubation, the PENG block is performed. Under sonographic guidance using a curvilinear probe, puncture will be performed in a lateromedial direction until the needle tip reaches the plane between the iliopsoas tendon and periosteum and between the anterior inferior iliac spine and iliopubic eminence. After a negative aspiration test, the blinded test item will be injected in the plane beneath the iliopsoas muscle. Patients will be randomly assigned to receive the test item (20 mL of ropivacaine 0.5%, Naropin). The anesthesiologist and the surgeon are blinded to the product injected.

ll patients will undergo the same preoperative, standardized protocol. Upon arrival to the operating room, patients will be placed in supine position. Routine, standard pre-medication will be applied before induction of general anesthesia. After intubation, the PENG block is performed. Under sonographic guidance using a curvilinear probe, puncture will be performed in a lateromedial direction until the needle tip reaches the plane between the iliopsoas tendon and periosteum and between the anterior inferior iliac spine and iliopubic eminence. After a negative aspiration test, the blinded test item will be injected in the plane beneath the iliopsoas muscle. Patients will be randomly assigned to receive the placebo (20 mL of NaCL 0.9%). The anesthesiologist and the surgeon are blinded to the product injected.

Using a ruler, the score is determined by measuring the distance (cm) on the 10-cm line between the "no pain" anchor and the patient's mark, providing a range of scores from 0 to 10. A higher score indicates greater pain intensity

The length of hospital stay is measured in days, from the day of surgery (day 0) to the patient's discharge from the hospital. Discharge occurs up to a maximum of 7 days after surgery when the 3 following criteria are met: the scar must be dry, the pain must no longer require morphine and the patient must be able to walk with crutches

Length of stay at the hospital (in days) from the day of the surgery (day 0) to the day of discharge, up to a maximum of 7 postoperative days

Inclusion Criteria: Anterior total hip arthroplasty for hip osteoarthritis Surgical hip dislocation for femoro-acetabular impingement (type cam-/pincer) Age 16-85 years American Society of Anesthesiologists (ASA) physical status 1 to 3 Exclusion Criteria: Patient refusal/no informed consent Inability to give informed consent Lateral approach for total hip arthroplasty Bilateral procedure Additional osteotomies of the femur and/or acetabulum Previous hip & pelvis surgery Chronic opioid users Known allergy or intolerance to medications used in the trial (local anesthetic, opioid) Infection at the injection site Body mass index > 40kg/m2 Spinal anesthesia

The IPD and results of this study will be presented at national and international orthopedic meetings and will be submitted to highly-ranked peer reviewed orthopedic journals.

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