Osteoarthritis Knee Pain
Conditions
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
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.
Interventions
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 anesthesia (2% lidocaine) is applied. Lesions are performed at 85°C for 90 seconds per site. The radiofrequency generator used is CE-marked for pain procedures. The study evaluates a novel targeting protocol, not the safety or effectiveness of the device itself. No fluoroscopy is used. The procedure is performed once. Participants are followed for two years to assess outcomes.
Sponsors
Study design
Eligibility
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Knee Pain Intensity (Numeric Pain Rating Scale - NPRS) | Baseline to 3 months post-procedure | Change in patient-reported knee pain at rest and during movement, measured using an 11-point Numeric Pain Rating Scale (0 = no pain, 10 = worst imaginable pain). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Physical Function (WOMAC Functional Subscale) | Baseline to 3 months, 6 months, 1 year, and 2 years post-procedure | Change in physical function as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Physical Function Subscale. The WOMAC is a validated, self-reported questionnaire assessing functional limitations due to knee osteoarthritis. This subscale includes 17 items, each scored on a Likert scale from 0 to 4. The total score ranges from 0 to 68, with higher scores indicating worse physical function. |
| Sustained Pain Reduction (Numeric Pain Rating Scale) | Baseline to 1 week, 1 month, 3 months, 6 months, 1 year, and 2 years post-procedure | Change in pain intensity over time as measured by the Numeric Pain Rating Scale (NPRS). The NPRS is an 11-point scale ranging from 0 to 10, where 0 represents no pain and 10 represents worst imaginable pain. Patients will report their average knee pain intensity over the past 24 hours. Higher scores indicate worse pain. This outcome assesses the duration and consistency of the analgesic effect following the radiofrequency ablation procedure. |
| Incidence of Adverse Events | From procedure day to 2-year follow-up | Number and type of adverse events related to the intervention, including local site pain, edema, bruising, motor weakness, neuritis, or other complications. |
| Responder Rate (≥50% Pain Reduction) | Baseline to 3 months post-procedure | Proportion of participants achieving ≥50% reduction in NPRS at 3 months post-procedure compared to baseline. |
Countries
Portugal