"The Effect of Adductor Canal Block Performed With Postoperative Thigh Tourniquet Application on Pain After Total Knee Arthroplasty"

April 16, 2026 updated by: Müge Çakırca, Ankara Etlik City Hospital
The biggest fear for patients undergoing knee replacement surgery is that persistent pain felt at the back of the knee postoperatively. While regional anesthesia is generally successful at numbing the front of the knee, managing pain in the posterior (back) area is not always easy. In this study, we tested a new method designed to alleviate pain in the back of the knee and improve patient comfort.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

A New Solution for "Posterior" Pain After Knee Surgery To ensure patient comfort following knee replacement surgery, we routinely use ultrasound-guided injections of local anesthetics around the nerves of the knee to block pain signals. While this method is highly successful at eliminating pain in the anterior (front) part of the knee, studies have shown that the medication often fails to reach the deep posterior (back) compartments, leaving patients with persistent discomfort in that area.

In this study, we addressed a fundamental question: "How can we ensure the medication reaches those hard-to-access depths at the very back of the knee?"

To achieve this, we developed a simple yet highly effective technique. We applied a tourniquet-similar to a blood pressure cuff-to the upper leg and inflated it for a short period. We administered the medication, then released the tourniquet and performed a second application.

This controlled pressure on the upper leg acted as a barrier, preventing the anesthetic from migrating upward toward the groin and instead "pushing" it into the narrow passages at the back of the knee. By doing so, we enabled the medication to reach deep points that it typically cannot access on its own.

The Results:

As a result of this technique, we observed a significant reduction in stubborn posterior knee pain. Furthermore, our patients required substantially fewer potent painkillers (analgesics) during their recovery.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria Patients aged 40-85 years, with a BMI of 18-35 kg/m², and an ASA physical status of I-III who underwent total knee arthroplasty (TKA) under spinal anesthesia were included. Eligible participants were those who volunteered to participate and provided written informed consent.

Exclusion Criteria

To ensure methodological standardization, the following cases were excluded:

Patients undergoing revision surgery.

Those undergoing unicompartmental (unicondylar) knee replacement, as the severity of surgical trauma differs from total replacement.

Bilateral cases, to prevent potential bias in assessing postoperative opioid consumption and pain scores.

Additionally, patients were excluded if:

The surgical duration exceeded 180 minutes.

There was a known history of coagulopathy, peripheral neuropathy, or allergy to local anesthetics.

The spinal anesthesia was insufficient, requiring a conversion to general anesthesia.

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: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Standard Adductor Canal Block Group (S-ACB)
Participants received a standard ultrasound-guided distal adductor canal block. During the procedure, 20 mL of 0.25% bupivacaine was injected. In this group, no tourniquet application or additional pressure modification was performed prior to the injection. The technique relied on the natural and passive distribution of the local anesthetic within the canal.
Procedure: Standard Adductor Canal Block (S-ACB)
Participants received a standard ultrasound-guided distal adductor canal block. During the procedure, 20 mL of 0.25% bupivacaine was injected in a single dose without any tourniquet modification or additional pressure application. The technique relied on the natural, passive, and anatomical distribution of the local anesthetic within the adductor canal.
Experimental: Tourniquet-Assisted Adductor Canal Block Group (T-ACB)
Participants received an ultrasound-guided distal adductor canal block. During the procedure, a pneumatic tourniquet placed on the proximal thigh was inflated for 3-5 minutes (at a pressure of approximately 142-202 mmHg), and 20 mL of 0.25% bupivacaine was injected. Following this, the tourniquet was deflated, and a second 20 mL dose of 0.25% bupivacaine was administered. The aim of this modification was to enhance the distribution of the local anesthetic through the adductor hiatus toward the neural networks of the posterior knee (posterior fascial planes)
Procedure: Tourniquet-Assisted Adductor Canal Block (T-ACB) grou
Participants received an ultrasound-guided distal adductor canal block. The procedure was performed in two stages: First, a pneumatic tourniquet placed on the proximal thigh was inflated for 3-5 minutes (at a pressure of approximately 142-202 mmHg), during which 20 mL of 0.25% bupivacaine was injected. Subsequently, the tourniquet was deflated, and an additional 20 mL of 0.25% bupivacaine was administered, reaching a total volume of 40 mL. This technique aimed to enhance the distribution of the local anesthetic through the adductor hiatus to the popliteal plexus at the posterior aspect of the knee.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
This method aims to alleviate posterior knee pain and decrease overall VAS scores
Time Frame: At 3, 8, 12, and 24 hours post-block
Visual Analog Scale (VAS): A scale where patients rate their pain intensity from 0 (no pain) to 10 (unbearable pain).
At 3, 8, 12, and 24 hours post-block

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
To decrease cumulative opioid requirements and facilitate mobilization while preserving muscle strength
Time Frame: at 3,8,12,24. post-block hours
  1. Total Opioid Consumption Total Opioid Consumption (The total amount of morphine/tramadol required during the first 24 hours postoperatively).
  2. Preservation of Motor Function Preservation of Motor Function (Assessment of quadriceps muscle strength using the Bromage Scale).
  3. Time to First Mobilization Time to First Mobilization (The hour at which the patient first stood up or ambulated postoperatively).
at 3,8,12,24. post-block hours

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ankara Etlik City Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 15, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 16, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 10, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 20, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 20, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • AEŞH-EK-2025-245

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Data Availability Statement: There are no plans to share individual participant data. Research findings will be reported as collective analyses in scientific journals and academic theses.

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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