Cooled Radiofrequency Ablation of Genicular Nerves for Knee Osteoarthritis Pain: A Protocol for Patient Selection and Case Series

Abstract

BackgroundChronic knee pain from osteoarthritis (OA) is common in the aging and the obese population. Radiofrequency ablation of the genicular nerves has been introduced as a potential surgery-sparing treatment for chronic knee pain from OA, yet only two outcome studies have been published and optimal patient selection for this procedure has not been established.ObjectivesWe describe a standardized protocol for selecting patients for cooled radiofrequency ablation (C-RFA) of the genicular nerves, as well as the clinical outcomes of four patients ages 63-65 years.MethodsThe threshold for selection based on diagnostic genicular nerve block was ≥ 80% pain reduction. Following successful block, C-RFA of the genicular nerves was performed. Outcomes included pain, function, analgesic medication use, opioid use, and progression to total knee arthroplasty at a minimum of 6 month follow up.ResultsC-RFA of the genicular nerves after using the described selection protocol resulted in > 90% pain reduction, improved function and avoidance of surgery at 6 months in all four cases. All opioid and analgesic medication use decreased or was unchanged in all cases. No serious adverse events occurred.ConclusionsThe accompanying case series suggests that this protocol is deserving of randomized, prospective study.

Comparative Effectiveness Review of Cooled Versus Pulsed Radiofrequency Ablation for the Treatment of Knee Osteoarthritis: A Systematic Review

“…With the Medline and CEN-TRAL searches and review of references, a total of 17 studies were considered for this review. The degree of evidence regarding the efficacy of radiofrequency ablation in the literature was not substantially high -only 5 small-sized randomized controlled trials were identified with size ranging from 17 to 54 patients (6,8,(14)(15)(16). The remaining studies were retrospective (17)(18)(19)(20) and prospective (21)(22)(23)(24) observational case series and case reports (12,(25)(26)(27).…”

“…Two studies (6,15) did not sufficiently specify the nerve target for RFA. In a randomized controlled trial of 54 patients, Shen et al (6) investigated RFA plus injection of platelet-rich plasma and sodium hyaluronate compared to injection alone. The authors described their approach as "we applied RFTC to the peripheral nerve of the knee joint."…”

“…With the absence of a placebo control group, the only conclusion that can be drawn from this study is that low frequency RFA may be have a clinically significant edge over TENS for treatment of knee OA. Without a specific nerve target, it is difficult to make a concrete statement about the efficacy of RFA from these 2 trials, despite both being controlled trials that scored 8/14 (Shen et al [6]) and 6/14 (Alcidi et al [15]).…”

“…Four publications utilized ultrasound guidance during the ablation procedure, 3 of which utilized PRF (21,22,24) while Clendenen et al (20) utilized conventional RFA and Protzman et al (12) applied both methodologies during a conventional RFA procedure. Meanwhile, the other 5 studies (6,(14)(15)(16)18) did not use any imaging, but simply used physical exam landmarks or failed to clearly specify whether imaging was or was not used. Kesikburun et al (24) performed ultrasound-guided PRF targeting the genicular nerves on 9 patients.…”

“…Treatment options for patients with OA include conservative approaches, such as weight loss, physical therapy, and pharmacological interventions, while the more invasive approaches include intraarticular injections, joint preserving surgical treatment, and total knee arthroplasty (TKA). Despite these treatment options, patients with severe OA of the knee often suffer from refractory pain and look for other modalities besides surgical interventions (5,6).…”