Selective Nerve Ablation for Chronic Knee Pain: A Retrospective Study

NCT07835672 | Completed

• 1 other identifier: SAVE-KNEE-001
• Study Type: observational
• Target: 746
• Locations: 1 country
• Sites: 1

Brief Summary

SAVE-KNEE is a single-center retrospective observational cohort study evaluating outcomes of ultrasound-guided cryoneurolysis, radiofrequency ablation and chemical neurolysis for chronic knee pain in routine clinical care. The study uses existing clinical records from June 1, 2022 through May 14, 2026. May 14, 2026 is the fixed cutoff for both eligible treatment and follow-up observations. Later clinical observations are excluded from this analysis. The primary outcomes are changes from the pretreatment baseline in patient-reported 0-10 numeric rating scale (NRS) knee pain and WOMAC scores at available 1-, 6- and 12-month assessments before the cutoff. Secondary outcomes include pain response, documented adverse events and repeat procedures. Follow-up availability varies; a 12-month assessment is not required for inclusion. Treatment and follow-up were provided as routine clinical care funded by the Polish National Health Fund (NFZ), independently of this study. No treatment or additional visit is assigned for research purposes. Pain assessments were conducted in person or by telephone. When verbal assistance was needed, the final 0-10 rating was stated or confirmed by the patient.

Conditions

Knee Osteoarthritis; Chronic Knee Pain

Keywords

Cryoneurolysis; Radiofrequency Ablation; Chemical Neurolysis; Genicular Nerves; Ultrasound-Guided Neurolysis; WOMAC; Age-Associated Disease; Functional Decline; Numeric Rating Scale

Outcome Measures

Primary Outcomes (2)

• Change from baseline in patient-reported knee pain on a 0-10 numeric rating scale (NRS)

  Change from baseline in patient-reported knee pain on a 0-10 NRS at 1, 6 and 12 months. Higher scores indicate greater pain; a decrease indicates improvement. Assessments were conducted in person or by telephone. When patients had difficulty selecting a number, verbal assistance included questions about pain severity, percentage or fractional improvement, and confirmation of a proposed numerical value. The final recorded 0-10 value was always stated or verbally confirmed by the patient, rather than assigned solely by the clinician. The use and extent of assistance cannot be determined for individual observations from the available records. Baseline is the patient-reported pain rating obtained on the day of the procedure, before it was performed.

  Pretreatment baseline; 1 month (+/-7 days), 6 months (+/-14 days), and 12 months (+/-30 days) after the procedure; only assessments performed on or before May 14, 2026

• Change from baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score

  Change in WOMAC total score from baseline to available assessments at 1, 6 and 12 months. The full questionnaire contains 24 items scored 0 (none) to 4 (extreme): 5 pain, 2 stiffness and 17 physical-function items. Total scores range from 0 to 96; higher scores indicate worse symptoms and function, and a decrease indicates improvement. During in-person visits, patients completed the questionnaire themselves. During telephone follow-up, an assistant read all 24 questions sequentially, entered the patient's responses into an interactive worksheet, and the worksheet calculated the total score. Analyses use raw total scores in participants with the required baseline and follow-up WOMAC data.

  Pretreatment baseline; 1 month (+/-7 days), 6 months (+/-14 days), and 12 months (+/-30 days) after the procedure; only assessments performed on or before May 14, 2026

Secondary Outcomes (3)

• Number and proportion of treated knees with documented procedure-related adverse events or complications

  From the procedure until the earliest of 12 months after treatment, the last available follow-up, or May 14, 2026

• Proportion of treated knees with at least 50% reduction in knee pain intensity

  Pretreatment baseline; 1 month (+/-7 days), 6 months (+/-14 days), and 12 months (+/-30 days) after the procedure; only assessments performed on or before May 14, 2026

• Number and proportion of treated knees undergoing a repeat pain-relieving procedure

  From the index procedure until the earliest of 12 months after treatment, the last available follow-up, or May 14, 2026

Study Arms (1)

SAVE-KNEE Retrospective Cohort

Patients with chronic knee pain who underwent qualifying ultrasound-guided cryoneurolysis, radiofrequency ablation or chemical neurolysis of sensory nerves around the knee during routine care from June 1, 2022 through May 14, 2026. This closed retrospective cohort includes only clinical observations recorded for care provided on or before May 14, 2026, with baseline pain and at least one follow-up pain assessment within this period. Enrollment counts individual participants. Knee-level outcomes distinguish bilateral treatment and repeat procedures on the same knee. No treatment is assigned by the study.

Procedure: Ultrasound-Guided Cryoneurolysis; Procedure: Ultrasound-Guided Radiofrequency Ablation; Procedure: Ultrasound-Guided Chemical Neurolysis

Interventions

Ultrasound-Guided Cryoneurolysis PROCEDURE

Percutaneous ultrasound-guided cryoneurolysis targeting sensory nerves around the knee, performed as part of routine clinical care for chronic knee pain. The procedure uses controlled local cooling to produce temporary interruption of sensory nerve conduction. This observational study evaluates treatment documented in routine clinical records; no procedure is assigned for research purposes.

SAVE-KNEE Retrospective Cohort

Ultrasound-Guided Chemical Neurolysis PROCEDURE

Percutaneous ultrasound-guided chemical neurolysis targeting sensory nerves around the knee, performed as part of routine clinical care for chronic knee pain. A neurolytic agent is administered locally to interrupt nociceptive nerve transmission. This observational study evaluates treatment documented in routine clinical records; no procedure is assigned for research purposes.

SAVE-KNEE Retrospective Cohort

Ultrasound-Guided Radiofrequency Ablation PROCEDURE

Percutaneous ultrasound-guided radiofrequency ablation targeting sensory nerves around the knee, performed as part of routine clinical care for chronic knee pain. Radiofrequency energy is used to produce controlled thermal neurolysis of the targeted nerve. This observational study evaluates treatment documented in routine clinical records; no procedure is assigned for research purposes.

SAVE-KNEE Retrospective Cohort

Eligibility Criteria

• Age: 40 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients with chronic knee pain treated in routine outpatient care at Reh-Medica Rehabilitation Center in Warsaw, Poland, during June 1, 2022 through May 14, 2026, identified retrospectively from electronic and paper medical records. The population includes patients with symptomatic knee osteoarthritis and patients with persistent pain after total knee arthroplasty who underwent ultrasound-guided cryoneurolysis, radiofrequency ablation or chemical neurolysis. This closed retrospective analysis includes only treatment and follow-up observations from June 1, 2022 through May 14, 2026. Later clinical observations are excluded. No treatment is assigned for research purposes.

You may qualify if:

• Age 40 years or older at the time of the procedure.
• Documented chronic knee pain lasting more than 6 months.
• Baseline pain intensity of at least 4 points on the 0-10 NRS.
• Failure of at least 6 months of conservative treatment, including medication, physiotherapy or previous intra-articular injections.
• Positive response to a targeted diagnostic genicular nerve block, if performed according to routine center practice, defined as at least 50% pain reduction during the action of the local anesthetic.
• Receipt of routine ultrasound-guided cryoneurolysis, radiofrequency ablation or chemical neurolysis of sensory nerves around the knee.

You may not qualify if:

• Pregnancy.
• Active infection at the procedure site or advanced skin ulceration around the knee.
• Insufficient documentation to establish baseline pain or absence of any post-procedure follow-up assessment on or before May 14, 2026.
• Confirmed mechanical implant complications, including loosening or structural failure, or acute joint infection in patients after total knee arthroplasty.

Sponsors & Collaborators

• Michał Bartoszewicz: lead

Study Sites (1)

Reh-Medica Centrum Rehabilitacji

Warsaw, Poland

Location

MeSH Terms

Conditions

Osteoarthritis, Knee

Interventions

Transurethral Resection of Prostate

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases

Intervention Hierarchy (Ancestors)

Prostatectomy; Urologic Surgical Procedures, Male; Urologic Surgical Procedures; Urogenital Surgical Procedures; Surgical Procedures, Operative

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Sponsor-Investigator and Principal Investigator

Study Record Dates

• First Submitted: September 17, 2026
• First Posted: September 23, 2026
• Study Start: June 1, 2022
• Primary Completion: May 14, 2026
• Study Completion: May 14, 2026
• Last Updated: September 23, 2026

Record last verified: 2026-09

Locations

PL (1)