2.1

Sample size

Based on an examination of prior study findings indicating that participants who underwent total hip arthroplasty and underwent ultrasound-guided PENG had a shorter mean of first walking time postoperatively than those who underwent supra-inguinal FICB (19.6 (9.6) versus 26.5 (8.2), respectively), a minimum sample size of 44 patients was established utilizing power evaluation and sample size tools (PASS11) (version11.0.08) to estimate the sample size. Power was set at 80 %, and an alpha error of 5 % was used.

2.2

Study procedure

All patients underwent comprehensive clinical assessment prior to the procedure and were educated on the visual analogue scale (VAS), where 10 denotes the worst pain and 0 denotes no pain.

An intravenous line was inserted upon arrival to the operating room, a 10 ml/kg preload of lactated Ringer solution was administered within 30 min prior to the procedure, and 50 micrograms of fentanyl were administered intravenously for pain relief. All candidates were monitored by pulse oximetry, electrocardiography, non-invasive blood pressure, and urine output.

Spinal anesthesia was conducted under a completely sterile technique via the L3-L4 or L4-L5 intervertebral space with a 25-gauge Quincke needle and an intrathecal injection of 12.5–15 mg heavy bupivacaine in combination with 25 micrograms of fentanyl. Supplemental oxygen 2 L/Min was conducted on all candidates via nasal prongs. Assessment of the level of spinal anesthesia besides baseline hemodynamics was recorded. In case of failure of spinal anesthesia general anesthesia were given and the patient was subsequently excluded from the study.

The research included forty-four participants who met the specified inclusion criteria. Utilizing a table of computer-generated random numbers, they were categorized into two comparable groups of twenty-two patients each: group F and group P.

Group F: The patients underwent ultrasound-guided Facia Iliaca Compartment Block under strict aseptic conditions following spinal anesthesia. The procedure was performed with an ultrasound device equipped with a linear probe (8–13 MHz) manufactured by SonoSiteTM, Inc., Bothell, WA 98,021, USA. The probe was positioned transversely along the thigh, 1/3 of the total distance between the pubic tubercle and anterior superior iliac spine. An echogenic needle measuring 4 inches and 22 gauge (PAJUNK, SonoPlex STIM REF 001,185–71) was introduced in plane while the needle tip was observed penetrating the fascia lata and fascia iliaca with two distinct popping sensations. A 20 mL amount of 0.25 percent bupivacaine was injected, taking into account not to exceed the toxic dose of bupivacaine (2.5 mg/kg), following negative aspiration and ultrasound imaging of drug solution distribution in tissue planes.

Group P: The patients underwent ultrasound-guided Pericapsular Nerve Group block under strict aseptic conditions following spinal anesthesia. The procedure was performed utilizing the identical ultrasound device, which featured a linear probe positioned on the thigh in alignment with a line just below and parallel to the inguinal ligament. In order to locate the psoas tendon, the ilio-pubic eminence, and the anterior inferior iliac spine, the probe was subsequently rotated 45° An identical echogenic needle, measuring 4 inches in length and 22 gauge, was introduced into the musculofascial plane posterior to the pubic ramus and anterior to the psoas tendon. The tip of the needle was positioned in this plane. A 20 mL amount of 0.25 percent bupivacaine was injected, taking into account not to exceed the toxic dose of bupivacaine (2.5 mg/kg), following negative aspiration and ultrasound imaging of drug solution distribution in tissue planes.

All candidates were moved to the Post-Anaesthesia Care Unit after the procedure, where they were closely observed for HR, blood pressure, and oxygen saturation (Spo2) for 2 h then transferred to ward and received 1 g of paracetamol every 8 h as a postoperative analgesic standard medication.

The primary outcome of our study was the time needed for unaided mobilization of the patient utilizing the timed up and go test (TUG) that calculates the time taken to stand up from a chair, move 3 m, return to the chair and sit down unaided in seconds.

The secondary outcomes were:

• 1.
  

  The intensity of pain following surgery was assessed by Visual analogue score (VAS) in PACU and ward at the following time intervals postoperatively 1/2, 2, 4, 8, 12, 24 hrs and if the VAS was >3, the patient received 5 mg nalbuphine intravenously as rescue analgesia to be repeated within 20 min till VAS ≤ 3.

  
  
• 2.
  

  The patient’s overall postoperative rescue analgesic dosage.

  
  
• 3.
  

  Time till the first dose of rescue analgesia needed by the patient.

  
  
• 4.
  

  The postoperative anesthetic complications related to the anesthetic procedure, such as hematoma at the site of injection, nausea, vomiting, and hypotension, for 24 h.

2.3

Statical analysis

Number and frequency were used to describe the qualitative data, whereas mean ± standard deviation (SD) was used to provide the quantitative data. The tests used were an independent-sample t -test, chi-square (X2) test, and Whitney U test.

The error margin accepted was established at 5 %, and the confidence interval of 95 % was chosen. Thus, if the p-value was <0.05, it was considered significant.