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

NCT ID: NCT07240402

Last Updated: 2025-11-20

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: PHASE1/PHASE2
• Total Enrollment: 15 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-11-17
• Study Completion Date: 2026-02-01

Brief Summary

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

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.

Conditions

Postoperative Analgesia; Morphine and Dexmedetomidine

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: SINGLE

Study Groups

Group D

Patients will receive ACB using 20 ml of bupivacaine 0.25%+ 0.5 µg/kg dexmedetomidine.

Group Type: EXPERIMENTAL

Adductor Canal Block (ACB) Only

Intervention Type: DRUG

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)

Group M

Patients will receive ACB using 20 ml of bupivacaine 0.25%

+0.1 mg/kg morphine.

Group Type: EXPERIMENTAL

Adductor Canal Block (ACB) Only

Intervention Type: DRUG

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)

Group C

Patients will receive ACB using 20 ml of bupivacaine 0.25% alone as a control group.

Group Type: EXPERIMENTAL

Adductor Canal Block (ACB) Only

Intervention Type: DRUG

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)

Interventions

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)

Intervention Type: DRUG

Other Intervention Names

adductor canal block

Eligibility Criteria

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.

• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Kafrelsheikh University

OTHER

Sponsor Role: lead

Responsible Party

Ashraf Abd El-Nasser Abd El-Hamid

Ashraf Elrewany

Responsibility Role: PRINCIPAL_INVESTIGATOR

Central Contacts

Ashraf Abd El-Nasser Abd El-Hamid kamel El Rewany Anesthesia KafrElsheikh University Faculty of Medicine Anesthesia, Surg, MBBCH

Role: CONTACT

ashraf.elrewany2@gmail.com

+201061195395

Other Identifiers

KafrelsheikhU

Identifier Type: -

Identifier Source: org_study_id