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

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: Enrolling by invitation
• Conditions: Total Knee Arthroplasty for Gonarthrosis
• Intervention / Treatment: Procedure: Standard Adductor Canal Block (S-ACB); Procedure: Tourniquet-Assisted Adductor Canal Block (T-ACB) grou

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: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Ankara, Turkey (Türkiye), 06690
    • Ankara Etlik Şehir Hastanesi

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
This method aims to alleviate posterior knee pain and decrease overall VAS scores	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

Outcome Measure	Measure Description	Time Frame
To decrease cumulative opioid requirements and facilitate mobilization while preserving muscle strength	Total Opioid Consumption Total Opioid Consumption (The total amount of morphine/tramadol required during the first 24 hours postoperatively).; Preservation of Motor Function Preservation of Motor Function (Assessment of quadriceps muscle strength using the Bromage Scale).; 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

• Sponsor: Ankara Etlik City Hospital

Publications and helpful links

General Publications

• Sonawane K, Dixit H, Mistry T, Gurumoorthi P, Balavenkatasubramanian J. Anatomical and Technical Considerations of the Hi-PAC (Hi-Volume Proximal Adductor Canal) Block: A Novel Motor-Sparing Regional Analgesia Technique for Below-Knee Surgeries. Cureus. 2022 Feb 6;14(2):e21953. doi: 10.7759/cureus.21953. eCollection 2022 Feb.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2026
• Primary Completion (Estimated): April 15, 2026
• Study Completion (Estimated): April 16, 2026

Study Registration Dates

• First Submitted: April 10, 2026
• First Submitted That Met QC Criteria: April 16, 2026
• First Posted (Actual): April 20, 2026

Study Record Updates

• Last Update Posted (Actual): April 20, 2026
• Last Update Submitted That Met QC Criteria: April 16, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Total knee arthroplasty; Postoperative analgesia; Opioid consumption; adductor canal block
• Other Study ID 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