Osteo Arthritis KneeRADIOPHENOLNCT06094660
RFA or Chemical Neurolysis of the Genicular Nerves Compared to Conservative Treatment for Knee Pain Caused by OA
A study testing Diagnostic genicular nerve block, Genicular nerve block with Radiofrequency Ablation (RFA) and Genicular nerve block with Phenol 6% in people with Osteo Arthritis Knee and Knee Pain Chronic, run by Dijklander Ziekenhuis at 2 sites in Netherlands.
Trial summary
A randomised controlled triall (RCT) with three parallel arms comparing the functional outcome of chemical ablation with phenol and radiofrequency ablation (RFA) of the genicular nerves with conservative treatment in patients with chronic knee pain caused by osteoarthritis (OA). Read more about this study
- Who is it for?
- Ages 35 to 90 years
- Conditions the study is for
- Osteo Arthritis Knee, Knee Pain Chronic
- What is being tested?
- Diagnostic genicular nerve block, Genicular nerve block with Radiofrequency Ablation (RFA) and Genicular nerve block with Phenol 6%
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 192 participants
- Where
- 2 sitesNetherlands
- Study dates
- 27 Nov 2023to 1 Nov 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 35 to 90 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients of both sexes, >35 years who are not a candidate for TKA due to young age, old age, comorbidity or technical reasons.
- OKS < 30 on a scale from 0 (severe function) to 48 points (satisfactory function).
- Continued pain in the target knee that is moderate to severe (defined as NRS ≥ 6 on an 11-point NRS scale) either constantly or with motion despite at least 3 months of conservative treatments. Conservative treatment can include: active physiotherapy, pharmacological treatment of pain (acetaminophen or NSAIDs) and intra-articular corticosteroid infiltration.
- Radiologic confirmation of arthritis for the target knee. Defined as the Kellgren Lawrence (KL) score of 2 or more on X-ray or MRI.
Who cannot join
- Patient with prior ablation of the genicular nerves, prior partial, resurfacing, or TKA of the target knee (residual hardware).
- Patient with a history of neurovascular injury or recent trauma of the lower extremities.
- Patient with chronic widespread pain.
- Polyneuropathy and/or radicular pain in the lower extremities.
- Patient is currently implanted with a neurostimulator.
- Local or systemic infection (bacteraemia).
Show all 13Show fewer
- Uncontrolled immune suppression.
- Intra-articular injections (steroids, hyaluronic acid, platelet enriched plasma, stem cell, …) in the target knee within 90 days from randomisation.
- Arthroscopic debridement/lavage into the target knee within 180 days from randomisation.
- BMI<18,5 kg/m2 and patients with minimal subcutaneous tissue thickness that would not accommodate ablation with phenol or radio frequency (risk of skin burns).
- Allergies to products used during the procedure (lidocaine, phenol, contrast dye).
- Patients who have a planned TKA in the near future, defined as patients who already have agreed on a date for the TKA procedure.
- Patients with psychosocial problems as determined by the investigator.
Trial locations and contacts
2 sites in 1 country.
Netherlands2 sites, 2 recruiting
- Recruiting
Dijklander Ziekenhuis
Hoorn, North Holland, 1624NP
Gezina Oei, MD, PhD, g.t.m.l.oei@dijklander.nl
Paul de Wit, MD, p.r.dewit@dijklander.nl
- Not yet recruiting
Bravis Ziekenhuis
Roosendaal, 4708AE
Lars Elzinga, l.elzinga@bravis.nl
Jeroen van der Heiden, j.vdheiden@bravis.nl
About this study
Official title: Patients With Knee Pain Caused by Osteoarthritis: Comparison of Conservative Medical Management With RadioFrequency Ablation or Chemical Neurolysis of the Genicular Nerves With Phenol
A randomised controlled triall (RCT) with three parallel arms comparing the functional outcome of chemical ablation with phenol and radiofrequency ablation (RFA) of the genicular nerves with conservative treatment in patients with chronic knee pain caused by osteoarthritis (OA).
Read the detailed description
In guidelines for knee osteoarthritis (OA), conservative treatments are physical therapy, analgesics and intra-articular injections with corticosteroids. In severe OA and persisting symptomatic cases the golden standard is joint replacing surgery. A less invasive technique is ablation of the sensory (genicular) nerves of the knee. This technique is beneficial for younger patients as a bridge to surgery or patients that cannot undergo total knee arthroplasty (TKA) due to comorbid health conditions. Nerve ablation can either be done with chemical agents or thermal energy.
Although there are numerous studies on genicular nerve block for chronic knee pain caused by OA, there are just a few small studies that compare genicular nerve block with conservative treatment.To be able to determine if genicular nerve ablation is efficacious to serve the gap between conservative treatment and TKA, this randomised controlled trial (RCT) compares two forms of genicular nerve ablation (radiofrequency and phenolisation; intervention) with conservative treatment (control) up to 6 months after treatment.
- Conditions
- Osteo Arthritis Knee, Knee Pain Chronic
- Being tested
- Diagnostic genicular nerve block, Genicular nerve block with Radiofrequency Ablation (RFA), Genicular nerve block with Phenol 6%
- Keywords
- Pain, Thermal ablation, Phenol neurolysis, Genicular nerve
- Medical subject headings
- Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Diagnostic genicular nerve blockProcedure or surgery
Diagnostic block will be done with 1,5ml of Lidocaine 2% at the 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve.
Genicular nerve block with Radiofrequency Ablation (RFA)Procedure or surgery
Genicular nerve block with RFA will be performed at 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve.
Radiofrequency ablation (RFA) is performed by creating two RFA lesions at the 3 treatment sites (6 lesions in total) after local anesthesia with 1,5ml lidocaine 2%. The lesions are made by heating the 5mm active tip of the needle to 80°C for 90 seconds.
Genicular nerve block with Phenol 6%Procedure or surgery
Genicular nerve block with Phenol 6% will be performed at 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve.
Chemical ablation with phenol is done by injection of 1 ,5ml of phenol 6 % at the 3 target sites after infiltration with contrast dye to rule out intravascular injection. Because infiltration with phenol is painless, prior infiltration of the target site with al local anaesthetic is not necessary.
| Study group | Role | What they receive |
|---|---|---|
| Chemical ablation of the genicular nerves with Phenol 6% | Active comparator | Chemical ablation with phenol is done by injection of 1,5ml of phenol 6 % at the superomedial, the superolateral and the inferomedial genicular nerve. Receives: Procedure: Diagnostic genicular nerve block; Procedure: Genicular nerve block with Phenol 6% |
| Radiofrequency ablation (RFA) of the genicular nerves | Active comparator | In our study we will make two RFA lesions at every target with 80°C for 90 seconds with a 5mm active tip. So we will make 6 lesions in total. The targets are the superomedial, the superolateral and the inferomedial genicular nerve. Receives: Procedure: Diagnostic genicular nerve block; Procedure: Genicular nerve block with Radiofrequency Ablation (RFA) |
| Conservative treatment | No intervention | Examples of allowed conservative treatments during the study are patient education, physical therapy, weight loss and different pharmacological treatments. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Knee function measured with the Oxford Knee score (OKS)
Questionnaire with 12 items. Scores can range from 0 to 48, with 48 being the best outcome and a lower score indicates more functional limitations and pain.
Measured: During intake, before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Secondary outcomes (21)
Osteoartritis (OA) measured by the Western Ontario and McMaster Universities Arthritis Index (WOMAC)
We will use the WOMAC in the Likert version where question 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. So the sum of the scores ranges from 0 (the best) to 96 (the worse).
Measured: Before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Pain measured with the Numeric Rating Score (NRS)
NRS will be measured in rest and during the performance based tests.
Measured: In rest during intake and in rest and during performance based tests before and after the diagnostic nerve block (if applicable), before the intervention (if applicable), 6 weeks, 3 months, 6 months and 1 year after the intervention
30 seconds chair-stand test
During this test the total number of complete chair stands (up and down represents one stand) is counted. If at least a full stand is completed at 30 seconds this is counted in the total. If a person cannot stand even once then the score for the test is zero.
Measured: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
40 meters (4x10m) fast-paced walk test
The total time taken to walk the 4 × 10 m, excluding turns, of one trial is recorded and expressed as speed m/s by dividing distance (40 m) by time (seconds). Timing is paused during turns.
Measured: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
9-steps stair-climb test
Total time to ascend and descend steps for one trial is recorded in seconds.
Measured: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
Health related quality of life with the EQ-5D-5L
The EQ-5D descriptive system comprises the following five dimensions, each describing a different aspect of health: MOBILITY, SELF-CARE, USUAL ACTIVITIES, PAIN / DISCOMFORT and ANXIETY / DEPRESSION. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The respondent is asked to indicate his / her health state by checking the box against the most appropriate statement in each of the five dimensions. EQ-5D comprises a short questionnaire that is cognitively undemanding, taking only a few minutes to complete.
Measured: Before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Hospital Anxiety and Depression Scale (HADS)
The Dutch version of the HADS is a fourteen-item scale with seven items for anxiety (HADS-A) and seven items for depression (HADS-D) (49). Scoring for each item ranges from zero to three. A higher score indicates more anxiety or depression.
Measured: At T=0 (before intervention) and during T=3 (6 months after intervention)
Pain Catastrophizing Score (PCS)
The Pain Catastrophizing Scale (PCS) is a 13-item self-report questionnaire considered to be the most frequent and extensively studied tool to assess pain catastrophizing for chronic pain. Patients are asked to rate the degree to which they have any of the thoughts described in the questionnaire using a 5-point Likert scale ranging from 0 (never) to 4 (always). The total score is the sum of the scores for the individual items, and ranges from 0 to 52. Higher scores indicate a higher level of catastrophizing.
Measured: At T=0 (before intervention) and during T=3 (6 months after intervention)
Diagnostic block most appropriate cut-off value
The continuous results of the diagnostic nerve block in our study (percentage of pain relief) will be used to determine the best cut-off value for the positive outcome of the ablation. The cut-off value will be analysed with a receiver operating curve (ROC) analysis. Results equal or above this cut-off value are considered to predict a positive outcome of the ablation of the nerves, results below the cut-off value are considered to predict a negative outcome of the ablation of the nerve. For this analysis, a positive outcome of the ablation is defined as a MCID in OKS of 4.9 points at 3 months follow up.
Measured: Before and after the diagnostic block and during T=2 (3 months after intervention).
Patient satisfaction
The patient satisfaction with the result of treatment will be measured with a 5-point Likert scale (1-5). The patients will be asked to grade the statement 'I am satisfied with the result of the treatment' with the following options:
- Strongly disagree
- Disagree
- Neutral
- Agree
- Strongly agree
Measured: During the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Patient Global Impression of Change (PGIC)
The PGIC in pain and function will be measured with a 5-point Likert scale (1-5) on the applicable follow up visits. The patients will be asked to rate the following statements:
- Please imagine how you would have described your pain intensity before the procedure. How do you feel today as compared to baseline (Start of the study) as far as your knee pain caused by OA is concerned?
- Please imagine how you would have described the functionality of your knee before the procedure. How do you feel today as compared to baseline (start of the study) as far as your knee functionality caused by OA is concerned?
The options on the Likert scale are:
- much better
- slightly better
- no change
- slightly worse
- much worse
Measured: During the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Minimal Clinically Important Difference (MCID) of the OKS
We will use distribution and anchor based methods to determine the MCID on the patient reported outcomes of the OKS.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up. .
Minimal Clinically Important Difference (MCID) of the WOMAC
We will use distribution and anchor based methods to determine the MCID on the patient reported outcomes of the WOMAC.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) for the EQ-5D-5L
To determine the MCID on the patient reported outcomes of the EQ-5D-5L we will use an instrument defined method.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 30 seconds chair-stand test
We will use distribution and anchor based methods to determine the MCID of the 30 seconds chair-stand test.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 40 meters (4x10m) fast-paced walk test
We will use distribution and anchor based methods to determine the MCID of the 40 meters (4x10m) fast-paced walk test.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 9-steps stair-climb test.
We will use distribution and anchor based methods to determine the MCID of the 9-steps stair-climb test.
Measured: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Adverse events
The reported treatment related or probably treatment related adverse events will be listed as numbers with frequencies per treatment.
Measured: After the diagnostic block, after the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up.
Medication changes
The patients will be asked to report changes in the use of NSAIDs and opioids during the follow up visits. The results will be summarised as increased use, no change, decrease in use and use of opioids will be reported as MME.
Measured: Before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up.
Number of Total Knee Artroplasty's (TKA's)
The number of TKAs during the study follow up will be documented including the point in time since the intervention. If applicable, we will use the Kaplan-Meier estimator to estimate the survival function.
Measured: At 6 weeks, 3 months, 6 months and 12 months follow up.
Procedure time
The total procedure time of chemical ablation and RFA will be measured in minutes. The measurement starts as soon as the treating physician puts on his sterile gloves and will end when the sterile draping is taken off.
Measured: During the intervention visit (T=0)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Oct 2023
- Study start27 Nov 2023
- Primary completion1 Nov 2026 (estimated)
- Study completion1 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Osteo Arthritis KneeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 192 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Dijklander Ziekenhuis
- Sponsor type
- University, hospital or other
- Collaborators
- Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA), Bravis Hospital
- Responsible party
- Sponsor
- Investigators
- Gezina Oei, MD, PhD, Principal investigator, Academic Medical Centre AmsterdamMarkus Hollmann, Prof, Study chair, Academic Medical Centre Amsterdam
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06094660
- Sponsor's protocol ID
- DOC 045
- Acronym
- RADIOPHENOL
- Status last verified
- Dec 2023
- First submitted
- 12 Sep 2023
- Last updated
- 5 Dec 2023
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The study protocol and the final data will be published. Conditions for reuse apply: A de-identified dataset will be made available upon request to the corresponding author. The request must include ethics approval and a statistical analysis plan. An embargo period applies: The embargo period is at least 1 year after the publication of the original study.
Publications
Wit PR, Beek RV, Schokker M, Wensing C, Hollmann MW, Kallewaard JW, Oei G; RADIOPHENOL collaborators; Collaborative group name. Genicular nerve radiofrequency ablation, phenol neurolysis or conservative medical management in patients with knee osteoarthritis: protocol for the RADIOPHENOL randomised controlled multicentre trial with three parallel groups. BMJ Open. 2025 Jul 6;15(7):e094576. doi: 10.1136/bmjopen-2024-094576.
PubMed 40623740
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Patients With Knee Pain Caused by Osteoarthritis: Comparison of Conservative Medical Management With RadioFrequency Ablation or Chemical Neurolysis of the Genicular Nerves With Phenol
- ClinicalTrials.gov ID
- NCT06094660
- Acronym / sponsor ID
- RADIOPHENOL / DOC 045
- Conditions
- Osteo Arthritis Knee, Knee Pain Chronic
- Keywords
- Pain, Thermal ablation, Phenol neurolysis, Genicular nerve
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 192 participants (estimated)
- Lead sponsor
- Dijklander ZiekenhuisUniversity, hospital or other
- Collaborators
- Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA), Bravis Hospital
- Study start
- 27 Nov 2023 (actual)
- Primary completion
- 1 Nov 2026 (estimated)
- Study completion
- 1 Nov 2026 (estimated)
- First posted
- 23 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A randomised controlled triall (RCT) with three parallel arms comparing the functional outcome of chemical ablation with phenol and radiofrequency ablation (RFA) of the genicular nerves with conservative treatment in patients with chronic knee pain caused by osteoarthritis (OA).
Detailed description
In guidelines for knee osteoarthritis (OA), conservative treatments are physical therapy, analgesics and intra-articular injections with corticosteroids. In severe OA and persisting symptomatic cases the golden standard is joint replacing surgery. A less invasive technique is ablation of the sensory (genicular) nerves of the knee. This technique is beneficial for younger patients as a bridge to surgery or patients that cannot undergo total knee arthroplasty (TKA) due to comorbid health conditions. Nerve ablation can either be done with chemical agents or thermal energy.
Although there are numerous studies on genicular nerve block for chronic knee pain caused by OA, there are just a few small studies that compare genicular nerve block with conservative treatment.To be able to determine if genicular nerve ablation is efficacious to serve the gap between conservative treatment and TKA, this randomised controlled trial (RCT) compares two forms of genicular nerve ablation (radiofrequency and phenolisation; intervention) with conservative treatment (control) up to 6 months after treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Chemical ablation of the genicular nerves with Phenol 6% | Active comparator | Procedure: Diagnostic genicular nerve block, Procedure: Genicular nerve block with Phenol 6%Chemical ablation with phenol is done by injection of 1,5ml of phenol 6 % at the superomedial, the superolateral and the inferomedial genicular nerve. |
| Radiofrequency ablation (RFA) of the genicular nerves | Active comparator | Procedure: Diagnostic genicular nerve block, Procedure: Genicular nerve block with Radiofrequency Ablation (RFA)In our study we will make two RFA lesions at every target with 80°C for 90 seconds with a 5mm active tip. So we will make 6 lesions in total. The targets are the superomedial, the superolateral and the inferomedial genicular nerve. |
| Conservative treatment | No intervention | –Examples of allowed conservative treatments during the study are patient education, physical therapy, weight loss and different pharmacological treatments. |
Who may qualify
- Ages
- 35 to 90 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adult patients of both sexes, >35 years who are not a candidate for TKA due to young age, old age, comorbidity or technical reasons.
- OKS < 30 on a scale from 0 (severe function) to 48 points (satisfactory function).
- Continued pain in the target knee that is moderate to severe (defined as NRS ≥ 6 on an 11-point NRS scale) either constantly or with motion despite at least 3 months of conservative treatments. Conservative treatment can include: active physiotherapy, pharmacological treatment of pain (acetaminophen or NSAIDs) and intra-articular corticosteroid infiltration.
- Radiologic confirmation of arthritis for the target knee. Defined as the Kellgren Lawrence (KL) score of 2 or more on X-ray or MRI.
Key exclusion criteria (13 listed)
- Patient with prior ablation of the genicular nerves, prior partial, resurfacing, or TKA of the target knee (residual hardware).
- Patient with a history of neurovascular injury or recent trauma of the lower extremities.
- Patient with chronic widespread pain.
- Polyneuropathy and/or radicular pain in the lower extremities.
- Patient is currently implanted with a neurostimulator.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Diagnostic genicular nerve blockDiagnostic block will be done with 1,5ml of Lidocaine 2% at the 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve. | Procedure or surgery | Chemical ablation of the genicular nerves with Phenol 6%, Radiofrequency ablation (RFA) of the genicular nerves |
| Genicular nerve block with Radiofrequency Ablation (RFA)Genicular nerve block with RFA will be performed at 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve. Radiofrequency ablation (RFA) is performed by creating two RFA lesions at the 3 treatment sites (6 lesions in total) after local anesthesia with 1,5ml lidocaine 2%. The lesions are made by heating the 5mm active tip of the needle to 80°C for 90 seconds. | Procedure or surgery | Radiofrequency ablation (RFA) of the genicular nerves |
| Genicular nerve block with Phenol 6%Genicular nerve block with Phenol 6% will be performed at 3 target sites: the superomedial, the superolateral and the inferomedial genicular nerve. Chemical ablation with phenol is done by injection of 1 ,5ml of phenol 6 % at the 3 target sites after infiltration with contrast dye to rule out intravascular injection. Because infiltration with phenol is painless, prior infiltration of the target site with al local anaesthetic is not necessary. | Procedure or surgery | Chemical ablation of the genicular nerves with Phenol 6% |
Primary outcome
Knee function measured with the Oxford Knee score (OKS)
Time frame: During intake, before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Questionnaire with 12 items. Scores can range from 0 to 48, with 48 being the best outcome and a lower score indicates more functional limitations and pain.
21 secondary outcomes
Osteoartritis (OA) measured by the Western Ontario and McMaster Universities Arthritis Index (WOMAC)
Time frame: Before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Pain measured with the Numeric Rating Score (NRS)
Time frame: In rest during intake and in rest and during performance based tests before and after the diagnostic nerve block (if applicable), before the intervention (if applicable), 6 weeks, 3 months, 6 months and 1 year after the intervention
30 seconds chair-stand test
Time frame: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
40 meters (4x10m) fast-paced walk test
Time frame: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
9-steps stair-climb test
Time frame: Before and after the diagnostic block, before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up. In the conservative treatment group this will only be done at the applicable follow up dates.
Health related quality of life with the EQ-5D-5L
Time frame: Before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Hospital Anxiety and Depression Scale (HADS)
Time frame: At T=0 (before intervention) and during T=3 (6 months after intervention)
Pain Catastrophizing Score (PCS)
Time frame: At T=0 (before intervention) and during T=3 (6 months after intervention)
Diagnostic block most appropriate cut-off value
Time frame: Before and after the diagnostic block and during T=2 (3 months after intervention).
Patient satisfaction
Time frame: During the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Patient Global Impression of Change (PGIC)
Time frame: During the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).
Minimal Clinically Important Difference (MCID) of the OKS
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up. .
Minimal Clinically Important Difference (MCID) of the WOMAC
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) for the EQ-5D-5L
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 30 seconds chair-stand test
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 40 meters (4x10m) fast-paced walk test
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Minimal Clinically Important Difference (MCID) of the 9-steps stair-climb test.
Time frame: MCIDs will be determined for our population on T=1 (6weeks), T=2 (3 months) and T=3 (6 months) follow up.
Adverse events
Time frame: After the diagnostic block, after the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up.
Medication changes
Time frame: Before the intervention (T=0), and at 6 weeks, 3 months, 6 months and 12 months follow up.
Number of Total Knee Artroplasty's (TKA's)
Time frame: At 6 weeks, 3 months, 6 months and 12 months follow up.
Procedure time
Time frame: During the intervention visit (T=0)
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Dec 2023.
- Derived from this study: PubMed 40623740Wit PR, Beek RV, Schokker M, Wensing C, Hollmann MW, Kallewaard JW, Oei G; RADIOPHENOL collaborators; Collaborative group name. Genicular nerve radiofrequency ablation, phenol neurolysis or conservative medical management in patients with knee osteoarthritis: protocol for the RADIOPHENOL randomised controlled multicentre trial with three parallel groups. BMJ Open. 2025 Jul 6;15(7):e094576. doi: 10.1136/bmjopen-2024-094576.
- Individual participant dataSharing planned: Yes. The study protocol and the final data will be published. Conditions for reuse apply: A de-identified dataset will be made available upon request to the corresponding author. The request must include ethics approval and a statistical analysis plan. An embargo period applies: The embargo period is at least 1 year after the publication of the original study.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gezina Oei, MD, PhD principal investigator
Academic Medical Centre Amsterdam
Markus Hollmann, Prof study chair
Academic Medical Centre Amsterdam
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Diagnostic genicular nerve block, Genicular nerve block with Radiofrequency Ablation (RFA) and Genicular nerve block with Phenol 6% in people with Osteo Arthritis Knee and Knee Pain Chronic, run by Dijklander Ziekenhuis at 2 sites in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 5 Dec 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Gezina Oei, MD,PhD (0031229257257, g.t.m.l.oei@dijklander.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Knee function measured with the Oxford Knee score (OKS) (time frame: During intake, before the intervention or study start in conservative group (T=0) and during the follow up visits (T=1 at 6weeks, T=2 at 3 months, T=3 at 6 months and T=4 at 12 months after the intervention or study start).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06094660, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Dec 2023.