Clinical trial NCT06934421: Revised Targets for Knee Radiofrequency Ablation
Official title: Segurança e eficácia de Nova Abordagem Ecoguiada de ablação Por radiofrequência Dos Nervos Geniculados
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Osteoarthritis Knee Pain
Keywords: Genicular nerve
Knee pain
Chronic pain
Knee osteoarthritis
Radiofrequency ablation
Ultrasound guidance
Interventional pain management
Joint degeneration
Nerve ablation
Image-guided procedures
Non-surgical treatment
Musculoskeletal intervention
Pain reduction
Functional improvement
Lead sponsor: Centro Hospitalar Universitario do Algarve
Sponsor class: OTHER
First posted: 2025-04-18
Enrollment: 60
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients from the community referred to the Physical and Rehabilitation Medicine department.

Brief summary: This research team is doing a study to learn more about a new way to treat long-term knee pain caused by joint damage. They are using a treatment called radiofrequency ablation (RFA). This is a procedure where doctors use heat to stop certain nerves from sending pain signals.

In this study, doctors will use ultrasound to guide a small needle to nerves around the knee, called genicular nerves. Then, they will apply heat to those nerves using radiofrequency energy to help reduce pain.

The team created this new method based on recent studies of knee anatomy. They want to find out if this method can safely reduce pain and help people with knee joint damage move better. The study includes people who have moderate to severe knee damage and still have pain after trying medicine, physical therapy, or joint injections.

Each person in the study will have the treatment once. The research team will follow each person for two years. During this time, people in the study will answer simple questions about their knee pain and how it affects their daily life. The researchers will collect this information before the treatment and several times after it. One week after the procedure, the team will call each person to ask how they are feeling and check for any side effects.

Possible benefits of the study include less knee pain and easier movement. Possible risks include pain during the procedure, bruising, swelling, or short-term worsening of pain. Rare risks include nerve problems, weakness, bone damage, or allergic reaction.

The study is free for participants, and there is no payment. Taking part is voluntary. Anyone can stop being in the study at any time without affecting their medical care. The research team will keep all personal information private and secure.

Detailed description: This study applies a modified ultrasound-guided radiofrequency ablation (RFA) protocol for targeting the genicular nerves, informed by recent anatomical research. Conventional genicular nerve RFA techniques commonly rely on fluoroscopic or ultrasound guidance based on standard anatomical landmarks. However, cadaveric studies-such as those by Fonkoue et al. (2021)-have shown that these conventional approaches frequently miss the intended nerves, particularly the superomedial and superolateral branches, leading to inconsistent or suboptimal outcomes.

To address these limitations, this protocol incorporates revised probe positioning and alternative bony landmarks aligned with verified nerve pathways. The updated targeting strategy is designed to improve the precision and reproducibility of genicular nerve localization using high-resolution musculoskeletal ultrasound.

The procedure begins with ultrasound identification of the target genicular nerves. Once confirmed, a local anesthetic (2% lidocaine, 20-40 mg per site) is infiltrated to minimize discomfort. Thermal lesioning is then performed using standard 20G RF cannulas at 85°C for 90 seconds. Sensory stimulation (0.2-0.5 V) is used to verify appropriate referral patterns, and motor stimulation (2.0 V) is applied to rule out motor involvement before lesioning. If motor responses are elicited, repositioning or procedure cancellation is considered.

This anatomically informed technique aims to enhance procedural accuracy and consistency. By integrating cadaver-based nerve mapping with real-time ultrasound imaging, the approach has the potential to improve treatment effectiveness while maintaining a strong safety profile. The study will contribute clinical data supporting the feasibility and utility of this refined targeting method in managing knee pain related to joint degeneration.

Eligibility criteria: Inclusion Criteria:

* Patients with chronic knee pain related to radiographic knee osteoarthritis, Kellgren-Lawrence (KL) grade III or IV, who are refractory to conservative treatment.

(Refractoriness to conservative treatment is defined as:

* Persistent pain and functional limitation after undergoing knee-targeted physiotherapy and analgesic medication in accordance with clinical guidelines for osteoarthritis \[e.g., paracetamol, nonsteroidal anti-inflammatory drugs, and other drugs as deemed appropriate by the treating physician\];
* Persistent pain and functional limitation after intra-articular corticosteroid injections or limited success with such interventions.)

Exclusion Criteria:

* Patients with previous knee arthroplasty
* Patients who have undergone prior radiofrequency (RF) ablation
* Significant psycho-emotional disorders
* Addictive behaviors
* Generalized pain
* Nociplastic pain
* Presence of a pacemaker
* Presence of osteosynthesis material in the knee or adjacent anatomical regions

Primary outcomes:
measure: Change in Knee Pain Intensity (Numeric Pain Rating Scale - NPRS)
timeFrame: Baseline to 3 months post-procedure
Secondary outcomes:
measure: Change in Physical Function (WOMAC Functional Subscale)
timeFrame: Baseline to 3 months, 6 months, 1 year, and 2 years post-procedure
measure: Sustained Pain Reduction (Numeric Pain Rating Scale)
timeFrame: Baseline to 1 week, 1 month, 3 months, 6 months, 1 year, and 2 years post-procedure
measure: Incidence of Adverse Events
timeFrame: From procedure day to 2-year follow-up
measure: Responder Rate (≥50% Pain Reduction)
timeFrame: Baseline to 3 months post-procedure
Other outcomes:
Locations:
city: Faro
country: Portugal
facility: Serviço de Medicina Física e de Reabilitação - Hospital de Faro - Unidade Local de Saúde do Algarve
city: Lisboa
country: Portugal
facility: Serviço de Medicina Física e de Reabilitação - Hospital de São Francisco Xavier - Unidade Local de Saúde de Lisboa Ocidental
Study officials:
affiliation: Unidade Local de Saude do Algarve / Centro Hospitalar Universitario Algarve
name: Manuel Tomás Farinha Caroço, Medical Doctor
role: PRINCIPAL_INVESTIGATOR
References:
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citation: Pardal, Margarida Alexandra Rodrigues. Adaptação cultural para português europeu do Western Ontario and McMaster Universities Arthritis Index (WOMAC). Master's Thesis 2023;
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citation: Tran J, Peng P, Agur A. Evaluation of nerve capture using classical landmarks for genicular nerve radiofrequency ablation: 3D cadaveric study. Reg Anesth Pain Med. 2020 Nov;45(11):898-906. doi: 10.1136/rapm-2020-101894. Epub 2020 Sep 14.
citation: Tran J, Peng PWH, Chan VWS, Agur AMR. Overview of Innervation of Knee Joint. Phys Med Rehabil Clin N Am. 2021 Nov;32(4):767-778. doi: 10.1016/j.pmr.2021.05.011. Epub 2021 Jul 14.
citation: Fonkoue L, Stoenoiu MS, Behets CW, Steyaert A, Kouassi JK, Detrembleur C, Cornu O. Validation of a new protocol for ultrasound-guided genicular nerve radiofrequency ablation with accurate anatomical targets: cadaveric study. Reg Anesth Pain Med. 2021 Mar;46(3):210-216. doi: 10.1136/rapm-2020-101936. Epub 2020 Dec 3.
citation: Fonkoue L, Behets C, Kouassi JK, Coyette M, Detrembleur C, Thienpont E, Cornu O. Distribution of sensory nerves supplying the knee joint capsule and implications for genicular blockade and radiofrequency ablation: an anatomical study. Surg Radiol Anat. 2019 Dec;41(12):1461-1471. doi: 10.1007/s00276-019-02291-y. Epub 2019 Jul 23.