The goal of this clinical trial is to compare two regimens of the pericapsular nerve group (PENG) block, an ultrasound-guided injection of local anaesthetic targeting the nerves supplying the front of the hip joint, for postoperative pain relief and quadriceps muscle function in patients undergoing primary unilateral total hip arthroplasty under spinal anaesthesia.
The PENG block was originally proposed as a motor-sparing technique. However, the standard 20 mL volume can spread to the femoral nerve and cause quadriceps weakness. Reducing the injected volume may limit this spread and better preserve quadriceps strength, but smaller volumes risk shorter analgesic duration. Adding dexamethasone to a low-volume injection may compensate for the reduced volume.
The main questions this trial aims to answer are:
* Does a low-volume PENG block (10 mL bupivacaine 0.25%) with 4 mg dexamethasone differ from a standard-volume PENG block (20 mL bupivacaine 0.25%) in the time to first rescue analgesia? * Does it differ in the incidence and severity of quadriceps weakness on the operated side?
Researchers will compare:
* Group A (standard-volume PENG block): 20 mL bupivacaine 0.25%. * Group B (low-volume PENG block with dexamethasone): 5 mL bupivacaine 0.5% plus 4 mL normal saline plus 4 mg dexamethasone in 1 mL, giving 10 mL of bupivacaine 0.25%.
Participants will:
* Receive spinal anaesthesia with heavy bupivacaine 0.5% and fentanyl. * Be randomly allocated to Group A or Group B using computer-generated random numbers. * Receive the PENG block under ultrasound guidance, performed by an anaesthesiologist expert in regional anaesthesia. * Receive intravenous paracetamol 1 g every 8 hours, with intravenous nalbuphine 5 mg as rescue analgesia when the pain score (NRS) is 4 or more. * Be assessed by an anaesthesiologist blinded to group allocation for pain scores at rest and on movement at 2, 6, 12 and 24 hours; quadriceps strength (MRC scale and straight leg raise) at 6, 12 and 24 hours compared with the preoperative baseline; total opioid consumption over the first 24 hours; and time to first ambulation within the first 24 hours.
The primary outcome is the time from completion of the PENG block to the first administration of rescue analgesia, recorded over the first 24 hours postoperatively. The study will be conducted at Ain Shams University Hospitals (El Demerdash Hospital) and will include 60 patients (30 per group), aged 50 to 70 years, ASA physical status I or II.
Physical status ASA I or II.
Age 50-70 years.
Patients scheduled for elective primary unilateral total hip arthroplasty under spinal anaesthesia.
No sex predilection.
Patient refusal.
Physical status ASA III or above.
Contraindications to spinal anaesthesia (coagulopathy, local infection at injection site, raised intracranial pressure).
Revision or bilateral total hip arthroplasty.
Parallel
Pericapsular nerve group (PENG) block
Procedure/SurgeryAn 80-100 mm, 22-gauge echogenic needle is advanced in-plane from lateral to medial into the plane between the psoas tendon and the iliopubic eminence under ultrasound guidance using a low-frequency curvilinear transducer (2-5 MHz), and the local anaesthetic is injected in increments after negative aspiration. Correct injectate spread deep to the psoas tendon will be confirmed sonographically.
Bupivacaine
DrugGroup A: 20 mL of bupivacaine 0.25% (50 mg). Group B: 5 mL of bupivacaine 0.5% (25 mg) diluted to a total injectate volume of 10 mL of bupivacaine 0.25%. Injected as the PENG block.
Dexamethasone
Drug4 mg dexamethasone in 1 mL added to the PENG block injectate in Group B (perineural).
Time to First Rescue Analgesia
The interval (in hours) from completion of the PENG block to the first administration of rescue analgesia (intravenous nalbuphine 5 mg, given when the Numerical Rating Scale pain score is 4 or more on a 0-10 scale, where 0 = no pain and 10 = worst possible pain).
Incidence and Severity of Quadriceps Weakness
Quadriceps strength on the operated side assessed using the Medical Research Council (MRC) scale (0-5, where 0 = no contraction and 5 = normal power) together with the ability to perform a straight leg raise, compared with the preoperative baseline. Clinically significant weakness is defined as a reduction of one or more MRC grades or inability to perform a straight leg raise.
Total Opioid Consumption
Total dose (mg) of rescue intravenous nalbuphine administered over the first 24 hours postoperatively.
Time to First Ambulation
Time (in hours) to first ambulation.
Click on the lead sponsor to view all of their trials.
This trial is not recruiting at the moment. You can still explore other options:
