An interventional study of CT-guided Cryoneurolysis of the Genicular Nerves in Arthroplasty, Replacement Material and Knee Arthritis Osteoarthritis, sponsored by Attikon Hospital. Recruiting at 1 site in Greece. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-20.
Sponsored by Attikon Hospital · Not applicable, Interventional, and Treatment
Approximately 20-30% of patients experience persistent pain after a Total Knee Arthroplasty (TKA). This study investigates whether percutaneous cryoneurolysis of genicular nerves can reduce pain and improve physical function when performed at least 24 hours before surgery. Participants will be randomized to receive either the cryoneurolysis procedure + TKA or TKA only. Results will be tracked for 6 months to see if the intervention improves long-term recovery and quality of life.
The current study is a prospective, single-center, randomized comparative trial (1:1 ratio). In the intervention group, cryoneurolysis is performed under imaging guidance targeting the upper lateral and medial and the lower medial genicular nerves. Under prophylactic antibiosis, and imaging guidance 17Gauge cryoprobes will be percutaneously placed at the level of the upper lateral and medial and the lower medial genicular nerves. The final position of each cryo probe will be verified with imaging guidance. Cryoneurolysis protocol will be 5min freezing-4min passive thawing-5min freezing. Post-interventional imaging will verify lack of potential immediate complications
3,227 studies on the registry are indexed under Chronic Pain; 729 are open to participants now.
This study's planned enrollment of 100 is above the median of 60 across 2,388 interventional studies indexed under Chronic Pain.
Browse Chronic Pain studies →Attikon Hospital is the lead sponsor of 86 studies on the registry; 17 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CT-guided cryoneurolysis of upper medial, upper lateral, and lower medial genicular nerves ≥24 hours before TKA.
Procedure: CT-guided Cryoneurolysis of the Genicular Nerves
Standard total knee arthroplasty without preoperative cryoneurolysis.
Percutaneous CT-guided cryoneurolysis using up to three cryoprobes (-20°C to -100°C) for temporary sensory nerve interruption.
Change in pain severity
Change in pain severity (Brief Pain Inventory-BPI) - Baseline to 1 month postoperatively. The BPI typically assesses two primary domains using a 0 to 10 numerical rating scale: Pain Intensity: Patients rate their pain at its "worst," "least," and "average" over the last 24 hours, as well as their pain "right now." 0 = No Pain 10 = Pain as bad as you can imagine Pain Interference: Patients rate how much their pain interferes with seven daily activities (General Activity, Mood, Walking Ability, Normal Work, Relations with others, Sleep, and Enjoyment of Life). 0 = Does not interfere 10 = Completely interferes Because higher numbers represent more intense pain and more significant disruption to life, a reduction in score over time is the goal of most clinical treatments.
Time frame: 1 month postoperatively
Knee Injury and Osteoarthritis Outcome Score
The Knee Injury and Osteoarthritis Outcome Score is a 42-item questionnaire designed to assess short-term and long-term consequences of knee injury. It covers five subscales: Pain, Symptoms, ADL, Sport/Rec, and QOL. Each subscale is transformed to a 0 to 100 scale. Unlike pain-only scales, higher scores mean a better outcome, with 100 representing a perfectly functional knee and 0 representing extreme knee problems.
Time frame: 3 and 6 months post-op
The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)
The Western Ontario and McMaster Universities Osteoarthritis Index is the "gold standard" for evaluating patients with hip and knee osteoarthritis. It measures 24 items divided into pain, stiffness, and physical function. Using a Likert scale (0-4 per item), the total score ranges from 0 to 96. For the WOMAC, higher scores mean a worse outcome, reflecting increased pain and significant physical disability.
Time frame: 3 and 6 months post-op
The Cardiovascular and Interventional Radiological Society of Europe (CIRSE) Classification System
The Cardiovascular and Interventional Radiological Society of Europe (CIRSE) Classification System is a tool used by clinicians to standardize the reporting of complications in interventional radiology. It ranks adverse events from Grade 1 to Grade 6. A Grade 1 signifies a minor issue with no therapy required, while a Grade 6 indicates patient death. Therefore, higher scores mean a worse outcome, representing a higher severity of medical complications.
Time frame: 6 months post-op
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — De-identified data will be available upon reasonable request following publication of primary results.
Supporting information: Study protocol
Time frame: IPD and supporting information will be available from June 1st, 2026. End date has not beed decided yet.
Started Jan 2026 (actual). Primary completion is estimated for Dec 2027, 23 months after the start.
Of 1,295 non-industry interventional studies with no phase under Chronic Pain, half reached primary completion within 20 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 39. This study's planned 23 months is above that.
Counting every sponsor, half of 1,378 studies reached it within 20 months; a quarter within 9 and three quarters within 38.
How these figures are worked out, and which studies are left out of them.
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