Selective Nerve Ablation for Chronic Knee Pain: A Retrospective Study

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.

Inclusion Criteria: * 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. * Advanced knee osteoarthritis, usually Kellgren-Lawrence grade III-IV, in a patient unsuitable for surgery because of comorbidities or declining arthroplasty; or persistent pain after total knee arthroplasty after exclusion of infection, implant loosening, mechanical failure and joint instability. * Index treatment between June 1, 2022 and May 14, 2026, with records documenting pretreatment baseline pain and at least one post-procedure follow-up pain assessment performed on or before May 14, 2026. Availability of WOMAC data determines inclusion in the functional-outcome analyses and is not required for the broader pain-outcome cohort. Exclusion Criteria: * 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.