Compare Morphine and Dexmedetomidine as Adjuvants to Bupivacaine in Ultrasound-guided ACB for Postoperative Analgesia After Knee Surgeries

November 16, 2025 updated by: Ashraf Abd El-Nasser Abd El-Hamid, Kafrelsheikh University

Comparative Study of Morphine and Dexmedetomidine as Adjuvants to Bupivacaine in Ultrasound-Guided Adductor Canal Block for Postoperative Analgesia After Knee Surgeries

This study aims to compare morphine and dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided ACB for postoperative analgesia after knee surgeries

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Knee surgeries are frequently performed operations that can lead to intense pain after the procedure (1). Early mobilization following knee surgery is associated with improved functional outcomes and a reduction in postoperative complications. As a result, achieving effective pain relief while preserving motor function is a primary goal in postoperative care for knee procedures (2).

A variety of strategies are employed for managing postoperative pain, including systemic opioid administration, epidural anesthesia, peripheral nerve blocks, and local infiltration of anesthetics (3).

However, systemic opioids are linked to several undesirable side effects such as nausea, vomiting, itching, sedation, and respiratory depression, which may hinder rehabilitation.

Similarly, epidural analgesia often results in complications like hypotension, urinary retention, and pruritus. The use of long-acting intrathecal opioids has also been associated with adverse events including bilateral motor blockade, tremors, and hypotension. Due to these issues, the reliance on systemic and intrathecal methods for postoperative pain control has been declining (4).

The adductor canal block (ACB), which targets the Hunter's canal, anesthetizes the saphenous and vastus medialis nerves, along with partial coverage of other sensory nerves like the femoral nerve, medial cutaneous nerve, and branches of the obturator nerve as they traverse the distal canal (5). ACB is largely considered a sensory block, affecting only the motor nerve to the vastus medialis, making it advantageous in preserving quadriceps strength during recovery (6, 7). Bupivacaine, a widely used long-acting amide local anesthetic, is frequently employed in peripheral nerve blocks such as the ACB due to its favorable pharmacokinetics.

Nonetheless, its analgesic duration may be insufficient for managing postoperative pain in surgeries with high nociceptive intensity (8). To extend its efficacy and enhance analgesic quality, several adjunctive agents have been explored, including opioids and α2-adrenergic agonists (9).

Morphine, a traditional opioid analgesic, acts on μ-opioid receptors to prolong analgesia and reduce local anesthetic requirements. Despite its effectiveness, its use is limited by opioid-related adverse effects like nausea, vomiting, pruritus, and respiratory depression. Furthermore, some studies report that morphine may not significantly improve postoperative pain control or functional recovery after knee surgery (10-12).

Dexmedetomidine, a highly selective α2-adrenergic receptor agonist, has been increasingly studied as an adjuvant in peripheral nerve blocks. When administered

perineurally, it has demonstrated potential to accelerate onset, prolong analgesia, reduce postoperative pain intensity, and minimize systemic opioid use, all while producing fewer systemic side effects (13). Its peripheral analgesic properties are thought to result from direct binding to α2-receptors at the nerve site (14).

Currently, there is limited research directly comparing the efficacy of morphine versus dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided ACB for postoperative analgesia following knee surgeries.

Study Type

Interventional

Enrollment (Estimated)

15

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

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

Study Contact

  • Name: Ashraf Abd El-Nasser Abd El-Hamid kamel El Rewany Anesthesia KafrElsheikh University Faculty of Medicine Anesthesia, Surg, MBBCH
  • Phone Number: +201061195395
  • Email: ashraf.elrewany2@gmail.com

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Both sexes.
  • American Society of Anesthesiologists (ASA) physical status I-II.
  • Body mass index (BMI) of 20-35 kg/m2.
  • Undergoing knee surgeries under spinal anesthesia.

Exclusion criteria:

  • Any known allergy or contraindication to local anesthetic.
  • History of substance abuse.
  • Decompansated cardiac, pulmonary, hepatic, renal disease.
  • Obese patients with BMI>35kg/m2.
  • Pregnant and lactating mothers.
  • Coagulopathies.
  • Local skin infections at the site of injection.

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: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group D
Patients will receive ACB using 20 ml of bupivacaine 0.25%+ 0.5 µg/kg dexmedetomidine.
Drug: Adductor Canal Block (ACB) Only

This study aims to compare morphine and dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided ACB for postoperative analgesia after knee surgeries. Primary outcome:

• Time to first rescue analgesia .

Secondary outcomes:

  • Total opioid consumption in 24 hours postoperatively.
  • Degree of pain using visual analogue scale (VAS).
  • Degree of patient satisfaction.
  • Incidence of complication A) Related to block Nerve Injury Vascular Puncture Hematoma B) Related to drug Local Anesthetic Systemic Toxicity (LAST)
Other Names:
  • adductor canal block
Experimental: Group M

Patients will receive ACB using 20 ml of bupivacaine 0.25%

+0.1 mg/kg morphine.
Drug: Adductor Canal Block (ACB) Only

This study aims to compare morphine and dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided ACB for postoperative analgesia after knee surgeries. Primary outcome:

• Time to first rescue analgesia .

Secondary outcomes:

  • Total opioid consumption in 24 hours postoperatively.
  • Degree of pain using visual analogue scale (VAS).
  • Degree of patient satisfaction.
  • Incidence of complication A) Related to block Nerve Injury Vascular Puncture Hematoma B) Related to drug Local Anesthetic Systemic Toxicity (LAST)
Other Names:
  • adductor canal block
Experimental: Group C
Patients will receive ACB using 20 ml of bupivacaine 0.25% alone as a control group.
Drug: Adductor Canal Block (ACB) Only

This study aims to compare morphine and dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided ACB for postoperative analgesia after knee surgeries. Primary outcome:

• Time to first rescue analgesia .

Secondary outcomes:

  • Total opioid consumption in 24 hours postoperatively.
  • Degree of pain using visual analogue scale (VAS).
  • Degree of patient satisfaction.
  • Incidence of complication A) Related to block Nerve Injury Vascular Puncture Hematoma B) Related to drug Local Anesthetic Systemic Toxicity (LAST)
Other Names:
  • adductor canal block

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Primary outcome:
Time Frame: 24 hours postoperatively.
• Time to first rescue analgesia .
24 hours postoperatively.

Collaborators and Investigators

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

Sponsor

Kafrelsheikh 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 (Estimated)

November 17, 2025

Primary Completion (Estimated)

January 1, 2026

Study Completion (Estimated)

February 1, 2026

Study Registration Dates

First Submitted

November 16, 2025

First Submitted That Met QC Criteria

November 16, 2025

First Posted (Actual)

November 20, 2025

Study Record Updates

Last Update Posted (Actual)

November 20, 2025

Last Update Submitted That Met QC Criteria

November 16, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • KafrelsheikhU

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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