Authors: L. McLean House II, MD1, David R. Walega, MD2, Ankur Garg, MD, MBA3, Imran M. Omar, MD3, Marc Korn, MD2, Rajiv D. Reddy, MD4, Dost M. Khan, MD2, Geeta Nagpal, MD2, Zachary L. McCormick, MD5Affiliated Institutions: (1)... [ view full abstract ]
Authors: L. McLean House II, MD1, David R. Walega, MD2, Ankur Garg, MD, MBA3, Imran M. Omar, MD3, Marc Korn, MD2, Rajiv D. Reddy, MD4, Dost M. Khan, MD2, Geeta Nagpal, MD2, Zachary L. McCormick, MD5
Affiliated Institutions: (1) Department of Anesthesia & Perioperative Care, University of California, San Francisco. CA, (2) Department of Anesthesiology. Northwestern University, Chicago, IL, (3) Department of Radiology. Northwestern University, Chicago, (4) Department of Physical Medicine and Rehabilitation. Northwestern University/ The Rehabilitation Institute of Chicago. Chicago, IL, (5) Department of Orthopaedic Surgery, University of California, San Francisco, CA
Background: Radiofrequency ablation of the genicular nerves has been introduced as a treatment for chronic knee pain, yet predictive factors of successful outcomes are poorly described. The authors sought to identify factors that predict clinical success following cooled radiofrequency ablation (cRFA) of the genicular nerves for the treatment of chronic knee pain due to osteoarthritis (OA).
Methods: A cross-sectional cohort study of patients with knee OA, anterior-posterior and lateral weight-bearing radiographs, pain numerical rating scale (NRS) score ≥4, diagnostic response (≥50% pain relief) to genicular nerve blocks, who underwent subsequent cRFA of the genicular nerves with minimum 6-month follow-up were included. Outcome data were collected by standardized phone survey. The primary outcome was a composite “treatment success” variable defined as: ≥30% reduction NRS score, patient global impression of change (PGIC) of “improved” or better, and lack of total knee arthroplasty (TKA). Multivariate logistic regression was used to identify covariates associated with treatment success including age, gender, body mass index, duration of symptoms, baseline NRS score, marital status, comorbid mood disorder, history of arthroscopy, knee compartment-specific Kelgren-Lawrence OA scores, and unilateral vs. bilateral procedures.
Results: Fifty-four patients (79 discrete knees), median age of 66 years [IQR: 62-75], 22% male, were included. Median time to follow-up was 6 [IQR 6-7] months. Forty-three treatments (54%; 95% CI: 43-65%) met success criteria. In the multivariate model, younger age (p=0.01), shorter symptom duration (p=0.04), higher baseline NRS score (p=0.02), and lack of prior arthroscopy (p=0.04) were associated with successful treatment (AU-ROC curve: 0.84).
Conclusions: Genicular nerve cRFA resulted in a 54% success rate at minimum 6-month follow-up using a composite definition. Younger age, shorter symptom duration, higher baseline NRS score, and lack of prior arthroscopy predicted success. These factors should be considered when selecting patients for genicular cRFA to treat painful knee OA.
