Proximal Spread in Adductor Canal Block(ACB)

NCT07595471 | Active Not Recruiting DMC

• 1 other identifier: 2024-KAEK-40
• Study Type: interventional
• Target: 68
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective, randomized clinical study is designed to evaluate the effects of two different injection levels of adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty. The study will be conducted at Ankara Etlik City Hospital and will include a total of 68 patients. All cases are limited to unilateral elective knee replacement surgeries performed under spinal anesthesia. In this study, the comparison will be based on the application of adductor canal block at two distinct injection levels. In both groups, blocks will be performed under ultrasound (USG) guidance using the same technical principles and standardized conditions; in the first group, the block will be administered at the level where the vasto-adductor membrane is first visualized, while in the second group, it will be performed at the level where the adductor longus ends. The type, concentration, and volume of local anesthetic used in both groups will be standardized as 20 mL of 0.25% bupivacaine. The groups will be compared in terms of the proximal spread of the local anesthetic based on the injection level, the area of spread at the apex of the iliopectineal fossa, the involvement of the femoral nerve, the incidence of postoperative falls, and analgesic consumption.

Conditions

Total Knee Anthroplasty; Postoperative Pain

Keywords

tka; adductor canal; block

Outcome Measures

Primary Outcomes (1)

• Proximal spread of local anesthetic

  The primary objective of this study is to compare the proximal spread of local anesthetic following ultrasound-guided adductor canal block performed at two distinct injection levels. In the first group, the injection will be administered at the level where the vastoadductor membrane is first visualized ultrasonographically in the proximal region. In the second group, the injection will be performed at the level where the adductor magnus and sartorius muscles first intersect.In both patient groups, the area of local anesthetic spread at the apex of the iliopectineal fossa will be measured in $cm\^2$ using ultrasonography. Additionally, the distance between the needle insertion point (injection level) and the apex of the iliopectineal fossa, as well as the distance from the needle insertion point to the most proximal point where the local anesthetic is ultrasonographically visualized, will be recorded in cm.

  The first postoperative hour

Secondary Outcomes (2)

• Pain Scores (Numeric Rating Scale)

  post-op hours 6 and 24

• Assessment of Motor Block

  Postoperative 24th hours

Study Arms (2)

Group 1: ACB at the proximal vasto-adductor membrane level (20 mL 0.25% bupivacaine)

ACTIVE COMPARATOR

Group 1: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the vasto-adductor membrane is first visualized.

Drug: Comparison of Proximal Adductor Canal Block

Group 2: Level of the end of the adductor longus

ACTIVE COMPARATOR

Group 2: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the adductor longus muscle ends.

Drug: Comparison True Distal Adductor Canal Block.

Interventions

Comparison of Proximal Adductor Canal Block DRUG

In this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the 'Femoral Triangle Block' in current publications,

Group 1: ACB at the proximal vasto-adductor membrane level (20 mL 0.25% bupivacaine)

Comparison True Distal Adductor Canal Block. DRUG

In this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the true 'Distal Adductor Canal Block' performed in accordance with contemporary anatomical criteria."

Group 2: Level of the end of the adductor longus

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• \* Patients aged \> 18 years.
• ASA physical status classification I-III.
• Patients scheduled for elective, unilateral total knee arthroplasty (TKA).
• Planned administration of spinal anesthesia.
• Ability to provide written informed consent.

You may not qualify if:

• Known hypersensitivity or allergy to local anesthetics.
• History of chronic pain syndrome or regular opioid consumption.
• Presence of peripheral neuropathy or neurological disorders affecting the femoral nerve.
• Coagulopathy or ongoing anticoagulant therapy.
• Active infection at the site of injection.
• Inability or refusal to provide written informed consent.

Sponsors & Collaborators

• Ankara Etlik City Hospital: lead

Study Sites (1)

Ankara Etlik City Hospital

Ankara, 06000, Turkey (Türkiye)

Location

Related Publications (1)

• Nair A, Dolan J, Tanner KE, Kerr CM, Jones B, Pollock PJ, Kellett CF. Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet. Br J Anaesth. 2018 Oct;121(4):890-898. doi: 10.1016/j.bja.2018.04.044. Epub 2018 Jun 18.

  PMID: 30236251 BACKGROUND

MeSH Terms

Conditions

Pain, Postoperative; Bites and Stings

Condition Hierarchy (Ancestors)

Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Pain; Neurologic Manifestations; Signs and Symptoms; Poisoning; Chemically-Induced Disorders; Wounds and Injuries

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assoc. Professor

Study Record Dates

• First Submitted: April 7, 2026
• First Posted: May 19, 2026
• Study Start: April 7, 2026
• Primary Completion (Estimated): May 30, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: May 19, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)