Knee Osteoartritis Genicular Nerve RF Ablation vs Alcohol Neurolysis (GEN-AL-RF)

April 10, 2026 updated by: Sakarya University

Comparison of Genicular Nerve Radiofrequency Ablation and Neurolytic Alcohol Injection for Chronic Knee Osteoarthritis Pain: A Randomized Controlled Trial

The GEN-AL-RF study is a randomized controlled trial designed to compare the clinical efficacy of two interventional techniques for managing chronic knee pain due to osteoarthritis. The study focuses on genicular nerve radiofrequency (RF) ablation versus neurolytic alcohol injection for pain blockade.

Patients diagnosed with knee osteoarthritis are randomly assigned to either the RF ablation group or the neurolytic alcohol group. The primary objective is to evaluate the superiority and duration of analgesic effects between these two methods. Clinical outcomes are assessed at baseline and at 1, 3, and 6 months post-procedure using the Numeric Rating Scale (NRS) for pain intensity, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for physical function, and the Short Form-12 (SF-12) for health-related quality of life.

The results of this study aim to provide high-quality evidence regarding the comparative effectiveness and long-term outcomes of genicular nerve RF and alcohol neurolysis in the clinical management of chronic knee osteoarthritis pain.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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

The GEN-AL-RF study investigates the clinical outcomes of two ultrasound-guided genicular nerve procedures in patients with Grade 3-4 knee osteoarthritis according to Kellgren-Lawrence criteria. Patients who have failed conservative treatment options are enrolled and randomly assigned to one of two intervention groups.

Under real-time ultrasound guidance, the superior medial, superior lateral, and inferior medial genicular nerves are targeted. In the Thermal Radiofrequency (RF) group, patients receive RF ablation at 75°C for 90 seconds per target nerve. In the Neurolytic Alcohol group, 1 mL of absolute ethanol is injected at each of the three anatomical targets. Both procedures are performed by experienced physicians using standardized needle placement techniques.

Clinical assessments are conducted at baseline and at follow-up intervals of 1, 3, and 6 months. The primary outcome is pain intensity measured by the Numeric Rating Scale (NRS). Secondary outcomes include physical function measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and health-related quality of life measured by the Short Form-12 (SF-12) survey. Safety is monitored throughout the study period by documenting any procedure-related adverse events.

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.
50

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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:

  • Age: Patients aged 45 to 85 years.
  • Diagnosis: Chronic knee pain for at least 6 months diagnosed with knee osteoarthritis according to American College of Rheumatology (ACR) criteria.
  • Radiological Grade: Grade 3 or 4 according to the Kellgren-Lawrence (K-L) classification.
  • Pain Severity: Baseline Numerical Rating Scale (NRS) score of 5 or higher.
  • Failure of Conservative Treatment: Inadequate response to conservative treatments (e.g., physical therapy, NSAIDs, or intra-articular injections) for at least 3 months.
  • Positive Diagnostic Block: At least 50% reduction in pain for minimum 24 hours following a prognostic genicular nerve block with local anesthetic.

Exclusion Criteria:

  • Previous Surgery: History of knee arthroplasty or major knee surgery on the affected side.
  • Specific Conditions: Presence of inflammatory arthritis (e.g., rheumatoid arthritis), gouty arthritis, or active infection at the injection site.
  • Neurological Deficit: Severe neurological or psychiatric disorders that may interfere with pain assessment.
  • Coagulopathy: Uncontrolled bleeding disorders or use of anticoagulant therapy that cannot be temporarily discontinued.
  • Recent Injections: Intra-articular steroid or hyaluronic acid injection within the last 3 months.
  • Allergy: Known allergy to local anesthetics, contrast agents, or ethyl alcohol.
  • Pacemaker: Presence of a cardiac pacemaker or implanted electronic device (specifically for the RFA group).

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel 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: Genicular Nerve Thermal Radiofrequency Ablation
Patients in this group will receive conventional thermal radiofrequency ablation of the superior medial, superior lateral, and inferior medial genicular nerves. The procedure will be performed at 80°C for 90 seconds per site under ultrasound guidance to achieve thermal neurocoagulation.
Other: genicular nerve block

Genicular nerve radiofrequency ablation : Patients will undergo ultrasound or fluoroscopy-guided radiofrequency ablation of the genicular nerves (superior medial, superior lateral, and inferior medial). The procedure involves placing RF cannulas at the target neural sites. Once the position is confirmed by sensory and motor stimulation, thermal radiofrequency lesioning will be performed to disrupt pain signal transmission.

Genicular nerve chemichal neurolysis: Patients will receive ultrasound or fluoroscopy-guided chemical neurolysis of the genicular nerves (superior medial, superior lateral, and inferior medial). Following correct needle placement confirmed by contrast spread or local anesthetic test block, a specific volume (1 mL per nerve) of ethyl alcohol (95-96% concentration) will be injected to achieve long-term neurolytic blockade of the target nerves.

Other Names:
  • genicular nerve chemical neurolysis
  • genicular nerve radiofrequency ablation
Experimental: Genicular Nerve Chemical Neurolysis (Alcohol)
Patients will receive chemical neurolysis of the superior medial, superior lateral, and inferior medial genicular nerves. 95% ethyl alcohol (1mL per site) will be injected at the target locations to achieve chemical neurodestruction of the sensory nerves.
Other: genicular nerve block

Genicular nerve radiofrequency ablation : Patients will undergo ultrasound or fluoroscopy-guided radiofrequency ablation of the genicular nerves (superior medial, superior lateral, and inferior medial). The procedure involves placing RF cannulas at the target neural sites. Once the position is confirmed by sensory and motor stimulation, thermal radiofrequency lesioning will be performed to disrupt pain signal transmission.

Genicular nerve chemichal neurolysis: Patients will receive ultrasound or fluoroscopy-guided chemical neurolysis of the genicular nerves (superior medial, superior lateral, and inferior medial). Following correct needle placement confirmed by contrast spread or local anesthetic test block, a specific volume (1 mL per nerve) of ethyl alcohol (95-96% concentration) will be injected to achieve long-term neurolytic blockade of the target nerves.

Other Names:
  • genicular nerve chemical neurolysis
  • genicular nerve radiofrequency ablation

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
Change from Baseline in Numeric Rating Scale (NRS) Score at 6 Months.
Time Frame: 1 month, 3 months, and 6 months.
The Numeric Rating Scale (NRS) is a segmented numerical version of the visual analog scale in which a respondent selects a whole number (0-10 integers) that best reflects the intensity of their pain. The score ranges from 0 (no pain) to 10 (worst possible pain). A decrease in score indicates pain relief.
1 month, 3 months, and 6 months.

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
Change from Baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Score
Time Frame: 1 month, 3 months, and 6 months post-procedure.
The WOMAC is a proprietary set of standardized questionnaires used to evaluate the condition of patients with osteoarthritis of the knee and hip, including segments for pain, stiffness, and physical function. Higher scores indicate worse outcomes.
1 month, 3 months, and 6 months post-procedure.
Change from Baseline in 12-Item Short Form Health Survey (SF-12) Score.
Time Frame: 1 month, 3 months, and 6 months post-procedure
The SF-12 is a self-reported outcome measure assessing health-related quality of life. It yields two summary scores: the Physical Component Summary (PCS) and the Mental Component Summary (MCS). Higher scores indicate better physical and mental health.
1 month, 3 months, and 6 months post-procedure

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.
Sakarya University

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 (Estimated)

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.
May 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.
December 1, 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.
December 30, 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 10, 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 17, 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 17, 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 10, 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

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.
  • E.567659-139

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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