NCT04472702 · University of California, Davis
Fluoroscopic Versus Ultrasound Guidance for Cooled Radiofrequency Ablation of Geniculate Nerves in Knee Osteoarthritis: A Randomized Control Trial
What this study is about
Cooled radiofrequency ablation (cRFA) of the knee geniculate nerves is a promising treatment option for knee osteoarthritis, but has variable effectiveness. Fluoroscopy is the typical guidance of choice, but uses bony landmarks to target these nerves which have variable positions around the knee.
View original scientific description
Cooled radiofrequency ablation (cRFA) of the knee geniculate nerves is a promising treatment option for knee osteoarthritis, but has variable efficacy. Fluoroscopy is the typical guidance of choice, but uses bony landmarks to target these nerves which have variable positions around the knee. Alternatively, ultrasound allows for targeting based on visualization of bony landmarks, the nerves, and their accompanying vascular structures, and thus may offer greater accuracy. However, there are few studies which directly compare the clinical efficacy of these two guidance options. This study will compare these two options.
Interventions
PROCEDURE
cRFA
cRFA intervention will occur under sterile conditions, the patient will be placed in a supine position on a table and a bolster to provide flexion in the treated knee joint. Skin and soft tissues will be anaesthetized with 2 mL 1% lidocaine at each of the three anatomic sites for cRFA, and a introducer needle will then be placed under ultrasound or fluoroscopic guidance to the SLG, SMG, and IMG nerves. Adjustments at these positions will be made when using ultrasound guidance in order to capture the geniculate nerve if the nerve and/or its accompanying vasculature can be directly visualized using greyscale or Doppler modes. When using ultrasound, the physician will note and record whether their positioning of the needle is based on bony landmarks, direct visualization of the nerve, and/or vascularity accompanying the nerve. Once the introducer needle is placed, the cRFA will be placed into the introducer needle.
Primary outcome measures
Numeric Pain Rating Scale
Time frame: Baseline up to 24 months
The objective is to rate patient's reported pain. The NPRS asks for a number between zero and ten that fits best to the subject's pain intensity, with zero as "no pain at all" and ten representing "the worst pain ever possible". It has a similar minimal clinically significant difference (20%) as the visual analog scale and can be administered via a phone interview.
Western Ontario and McMaster Universities Arthritis Index (WOMAC)
Time frame: Baseline up to 24 months
The objective is to measure the patient's reported functional status.The test questions are scored on a scale of 0-4, which correspond to: None (0), Mild (1), Moderate (2), Severe (3), and Extreme (4). The scores for each subscale are summed up, with a possible score range of 0-20 for Pain, 0-8 for Stiffness, and 0-68 for Physical Function. Usually a sum of the scores for all three subscales gives a total WOMAC score, however there are other methods that have been used to combine scores
PROMIS - Depression
Time frame: Baseline up to 24 months
The objective is to measure items relevant to the subject's mood, views of self, and engagement. The test version 8b has good responsiveness with a minimally important difference range of 3-3.1 in adults with knee OA.
PROMIS - Pain Interference
Time frame: Baseline up to 24 months
The objective is to measure the consequences of pain on the subject's life with a minimally important difference range of 2.35 to 2.4
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 1\) patients of either gender with primary knee OA of one or both knees fulfilling the diagnostic criteria for knee OA by the American College of Rheumatology,
- 2\) Kellgren-Lawrence score of two to four,
- 3\) reported NPRS pain intensity of at least four on most or all days of the past week
- 4\) pain resistant to conventional treatments which may include but is not limited to medications (e.g. acetaminophen, oral or topical non-steroidal anti-inflammatory drugs, opioids), physical therapy, and intra-articular injections (e.g. corticosteroids, hyaluronic acid, platelet-rich-plasma) for at least 3 months. In the case of bilateral knee OA, the most symptomatic knee will be treated and studied.
Exclusion criteria
- 1\) age \<35 years,
- 2\) non-English speaking patients,
- 3\) body mass index greater than 40,
- 4\) previous radiofrequency ablation procedure for the knee,
- 5\) active systemic or local infections at the site of needle/cRFA probe placement,
- 6\) previous knee joint replacement surgery,
- 7\) autoimmune or inflammatory cause of knee arthritis such as rheumatoid or psoriatic arthritis,
- 8\) non-ambulatory patients,
- 9\) patients who are unable to provide their own consent (e.g. dementia),
- 10\) unstable medical or psychiatric illness,
- 11\) patients with pacemakers, spinal cord stimulators, deep brain stimulators, or similar devices,
- 12\) patients seeking care as a part of workman's compensation or have litigation pending
- 13\) a negative response to diagnostic geniculate nerve lidocaine injections.
Where
- Sacramento, California
- Rochester, New York
Collaborators
American Medical Society for Sports Medicine
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 16, 2026 · Source of record for eligibility and locations