Periarticular Infiltration of Local Anesthetics Versus Pericapsular Nerve Group Block for Total Hip Replacement

This randomized trial is set out to compare the postoperative strength preservation capacity of local infiltration anesthesia (LIA) and pericapsular nerve group (PENG) block after performing a primary total hip arthroplasty (THA).

The hypothesis is that LIA represents a superior alternative to PENG block in terms of strength preservation but providing effective analgesia during the first 24 postoperative hours after THA. Hence, the trial was designed as a superiority study hypothesizing a fivefold reduction in quadriceps paresis/paralysis at 3 hours.

Patients who agree to participate in the protocol will be assigned to one group or another (LIA and PENG) through computationally generated block randomization. Outcome assessors blinded to randomization will perform all measurements.

All blocks, LIA or PENG, will be performed (or supervised) by one of the co-authors, an expert orthopedic surgeon or an expert anesthesiologist, respectively. Both blocks will be executed in the operating room, on the surgical table, under sedation, and with the barrier that separates the surgical field from the cranial area of the patient to keep the latter blind to the technique received.

All patients will undergo spinal anesthesia using 0.5% bupivacaine (10mg) plus 20 μg of fentanyl. Both groups will also receive tranexamic acid 1g intravenous (IV), ketoprofen 100mg IV, and acetaminophen 1gr IV. Propofol sedation guided with a targeted controlled infusion (TCI) model will be administered in order to obtain an adequate level of sedation.

All surgeries will be conducted by the same team of surgeons, performing a posterior approach technique in the lateral decubitus position.

In the recovery room, all patients will receive patient-controlled analgesia (morphine bolus = 1 mg; lockout interval = 8 minutes). On the surgical ward, all subjects will continue to receive acetaminophen (1 g per os every 6 hours), ketoprofen (100 mg per os every 8 hours) as well and patient-controlled analgesia (morphine bolus = 1 mg IV; lockout interval = 8 minutes).

Eligibility Criteria:
Inclusion Criteria:

* Age between 18 and 80 years
* American Society of Anesthesiologists classification 1-3
* Body mass index between 20 and 35 (kg/m2)

Exclusion Criteria:

* Adults who are unable to give their own consent
* Pre-existing neuropathy (assessed by history and physical examination)
* Coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets ≤ 100, International Normalized Ratio ≥ 01.4 or prothrombin time ≥ 50)
* Renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine ≥ 100)
* Hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases ≥ 100)
* Allergy to local anesthetics (LAs) or morphine
* Pregnancy
* Prior surgery in the inguinal area of the corresponding surgical side
* Previous hip arthroplasty due to hip fracture
* Chronic pain syndromes requiring opioid intake at home