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Enrolling by Invitation

NCT Number: NCT07539467

"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.

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Key information

Age range

40 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ankara Etlik Şehir Hastanesi

Ankara, 06690, Turkey (Türkiye)

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Tourniquet-Assisted Adductor Canal Block (T-ACB) grou

Procedure

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.

Standard Adductor Canal Block (S-ACB)

Procedure

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.

Primary outcomes

  1. 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).

Secondary outcomes

  1. To decrease cumulative opioid requirements and facilitate mobilization while preserving muscle strength

    Time frame: at 3,8,12,24. post-block hours

    • 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).

Sponsors and collaborators

Lead sponsor

Ankara Etlik City Hospital

Other Gov

Registry information

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Apr 20, 2026
Registry last updated
Apr 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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