Ultrasound-Guided PASC Block vs Femoral-Sciatic Nerve Block for Postoperative Analgesia After Total Knee Arthroplasty

December 22, 2025 updated by: Mahmoud Mohammed Elsayed Seif, Ain Shams University

Postoperative Analgesic Efficacy of Ultrasound Guided Para-sartorial Compartments (PASC) Block Versus Combined Femoral-Sciatic Nerve Block in Patients Undergoing Total Knee Arthroplasty: A Double-Blind Randomized Comparative Study

This randomized, double-blind comparative study evaluates postoperative analgesic efficacy and motor effects of ultrasound-guided para-sartorial compartments (PASC) block versus ultrasound-guided combined femoral-sciatic nerve block in patients undergoing total knee arthroplasty. The primary endpoint is total nalbuphine rescue analgesia consumption in the first 24 postoperative hours. Secondary endpoints include pain scores (NRS), motor function using a modified Bromage scale, block performance characteristics, and complications.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

62

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Egypt
    • Cairo Governorate
      • Cairo, Cairo Governorate, Egypt, 11511
        • Ain Shams University Hospitals

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 60 to 70 years
  • Scheduled for elective total knee arthroplasty under general anesthesia
  • American Society of Anesthesiologists physical status class I or II
  • Provided written informed consent

Exclusion Criteria:

  • American Society of Anesthesiologists physical status class III or IV
  • Pre-existing neurological abnormality of the lower extremity
  • Infection near the planned block site
  • History of psychiatric illness
  • History of drug abuse
  • Known allergy to local anesthetics or any study medications (bupivacaine, acetaminophen, ketorolac, nalbuphine)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Femoral Nerve Block plus Sciatic Nerve Block
After induction of general anesthesia, participants receive an ultrasound-guided single-shot femoral nerve block with 15 milliliters of 0.25% bupivacaine and an ultrasound-guided single-shot popliteal sciatic nerve block with 15 milliliters of 0.25% bupivacaine. Postoperative multimodal analgesia includes intravenous acetaminophen and ketorolac. Rescue analgesia is intravenous nalbuphine 5 milligrams when the Numeric Rating Scale pain score is 3 or higher, up to 20 milligrams per day.
Procedure: Ultrasound-Guided Femoral Nerve Block plus Sciatic Nerve Block
Single-shot ultrasound-guided femoral nerve block (15 milliliters of 0.25% bupivacaine) plus single-shot ultrasound-guided popliteal sciatic nerve block (15 milliliters of 0.25% bupivacaine), performed after induction of general anesthesia using sterile technique.
Experimental: Para-sartorial Compartments Block
After induction of general anesthesia, participants receive an ultrasound-guided single-shot para-sartorial compartments block using a single needle entry point with three injections of 0.25% bupivacaine: 10 milliliters inside the femoral triangle with periarterial and subsartorial spread, 10 milliliters in the subsartorial plane at the apex of the femoral triangle between sartorius and vastus medialis muscles, and 10 milliliters in the suprasartorial compartment at the level of the intermediate femoral cutaneous nerve (total 30 milliliters). Postoperative multimodal analgesia includes intravenous acetaminophen and ketorolac. Rescue analgesia is intravenous nalbuphine 5 milligrams when the Numeric Rating Scale pain score is 3 or higher, up to 20 milligrams per day.
Procedure: Ultrasound-Guided Para-sartorial Compartments Block
Single-shot ultrasound-guided para-sartorial compartments block performed after induction of general anesthesia using a single needle entry point and three injections of 0.25% bupivacaine: 10 milliliters in the femoral triangle with periarterial and subsartorial spread, 10 milliliters in the subsartorial plane at the apex of the femoral triangle, and 10 milliliters in the suprasartorial compartment at the level of the intermediate femoral cutaneous nerve (total 30 milliliters).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total Rescue Analgesia Requirement (Nalbuphine)
Time Frame: First 24 hours after surgery.
Total dose of intravenous nalbuphine (in milligrams) administered as rescue analgesia when the Numeric Rating Scale pain score is 3 or higher, with a maximum daily dose of 20 milligrams.
First 24 hours after surgery.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative Pain Intensity (Numeric Rating Scale)
Time Frame: 30 minutes after admission to the post-anesthesia care unit, and 3 hours, 6 hours, 12 hours, and 24 hours after surgery.
Pain intensity measured using the Numeric Rating Scale (0 = no pain, 10 = worst possible pain).
30 minutes after admission to the post-anesthesia care unit, and 3 hours, 6 hours, 12 hours, and 24 hours after surgery.
Motor Block Assessment (Modified Bromage Scale)
Time Frame: 2 hours, 4 hours, 6 hours, 12 hours, 18 hours, and 24 hours after surgery.
Motor function assessed using the modified Bromage scale: 1 = complete block (unable to move knee or feet), 2 = almost complete (able to move feet only), 3 = partial (just able to move knees), 4 = none (full flexion of knees and feet).
2 hours, 4 hours, 6 hours, 12 hours, 18 hours, and 24 hours after surgery.
Block Performance Time
Time Frame: During block performance immediately after induction of general anesthesia.
Time from ultrasound scanning start to completion of local anesthetic injection (in minutes).
During block performance immediately after induction of general anesthesia.
Block Duration
Time Frame: Up to 24 hours after surgery.
Duration of sensory and motor effects of the nerve block as assessed clinically (in hours).
Up to 24 hours after surgery.
Postoperative Nausea
Time Frame: First 24 hours after surgery.
Presence of postoperative nausea during the first postoperative day.
First 24 hours after surgery.
Postoperative Vomiting
Time Frame: First 24 hours after surgery.
Presence of postoperative vomiting during the first postoperative day.
First 24 hours after surgery.
Sedation (Richmond Agitation-Sedation Scale)
Time Frame: First 24 hours after surgery.
Richmond Agitation-Sedation Scale score ranging from +4 (combative) to -5 (unarousable); 0 indicates alert and calm.
First 24 hours after surgery.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ain Shams University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 1, 2023

Primary Completion (Actual)

February 1, 2024

Study Completion (Actual)

February 1, 2024

Study Registration Dates

First Submitted

December 22, 2025

First Submitted That Met QC Criteria

December 22, 2025

First Posted (Actual)

January 6, 2026

Study Record Updates

Last Update Posted (Actual)

January 6, 2026

Last Update Submitted That Met QC Criteria

December 22, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FMASU MD 29/2023

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data underlying the primary and secondary outcomes (including total nalbuphine rescue dose, Numeric Rating Scale pain scores, modified Bromage motor scores, procedure time, block duration, and adverse events) will be made available to qualified researchers upon reasonable request.

IPD Sharing Time Frame

Data will be available beginning 6 months after publication of the primary manuscript and will remain available for 5 years.

IPD Sharing Access Criteria

Requests should include a brief proposal and analysis plan. Access will be provided after review and approval by the study investigators and completion of a data use agreement. Data will be shared in a de-identified format.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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