Revised Targets for Knee Radiofrequency Ablation

Official title

Segurança e eficácia de Nova Abordagem Ecoguiada de ablação Por radiofrequência Dos Nervos Geniculados

Overview

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.

Interventions

• Device Ultrasound-Guided Genicular Nerve Radiofrequency Ablation
  This intervention involves a single-session ultrasound-guided thermal radiofrequency ablation of the superomedial, superolateral, and inferomedial genicular nerves in patients with moderate to severe knee osteoarthritis. Target points follow anatomical references described by Fonkoue et al. and validated in cadaveric studies, differing from classical approaches. Under ultrasound guidance, monopolar RF cannulas are placed, with sensory and motor stimulation confirming accurate positioning. Local

Primary outcome measures

• Change in Knee Pain Intensity (Numeric Pain Rating Scale - NPRS) [Time frame: Baseline to 3 months post-procedure]

Secondary outcome measures (4)

• Change in Physical Function (WOMAC Functional Subscale) [Time frame: Baseline to 3 months, 6 months, 1 year, and 2 years post-procedure]
• Sustained Pain Reduction (Numeric Pain Rating Scale) [Time frame: Baseline to 1 week, 1 month, 3 months, 6 months, 1 year, and 2 years post-procedure]
• Incidence of Adverse Events [Time frame: From procedure day to 2-year follow-up]
• Responder Rate (≥50% Pain Reduction) [Time frame: Baseline to 3 months post-procedure]

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

Portugal · 2 centers

• Serviço de Medicina Física e de Reabilitação - Hospital de Faro - Unidade Local de Saúde d — Faro
• Serviço de Medicina Física e de Reabilitação - Hospital de São Francisco Xavier - Unidade — Lisbon

Publications

• Cohen SP, Bhaskar A, Bhatia A, Buvanendran A, Deer T, Garg S, Hooten WM, Hurley RW, Kennedy DJ, McLean BC, Moon JY, Narouze S, Pangarkar S, Provenzano DA, Rauck R, Sitzman BT, Smuck M, van Zundert J, Vorenkamp K, Wallace MS, Zhao Z. Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group. Reg Anesth Pain Med. 2020 Jun;45(6):424- PMID 32245841
• Pardal, Margarida Alexandra Rodrigues. Adaptação cultural para português europeu do Western Ontario and McMaster Universities Arthritis Index (WOMAC). Master's Thesis 2023;
• De Cassai A, Dost B, Tulgar S. Enhancing the clarity and reproducibility of regional anesthesia techniques: a call for video integration in scientific publications. Reg Anesth Pain Med. 2025 Oct 6;50(10):842-843. doi: 10.1136/rapm-2024-105871. No abstract available. PMID 39043621
• 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. PMID 32928998
• 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. PMID 34593142
• 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. PMID 33273065
• 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. PMID 31338537

Identifiers

NCT: NCT06934421 · 025/2025

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗