A Technological Overview of Cooled Radiofrequency Ablation and its Effectiveness in the Management of Chronic Knee Pain

Abstract

Knee osteoarthritis (OA) is a painful and sometimes debilitating condition affecting an estimated 14 million people in the USA alone. Management of knee OA begins with conservative medical treatments and progresses to total knee arthroplasty. Managing pain until a patient is eligible for arthroplasty remains a key part of the treatment algorithm for knee OA. Cooled radiofrequency ablation has shown clinical effectiveness in managing knee OA pain, with a majority of patients experiencing upwards of 12 months of analgesic effect. Herein is presented an overview of the technology of cooled radiofrequency ablation and a summary of current clinical trials demonstrating the treatments effectiveness.

Efficacy and safety of radiofrequency treatment for improving knee pain and function in knee osteoarthritis: a meta-analysis of randomized controlled trials

“…The pulse generator of RF is a simple electrode structure that generates an electromagnetic field when an electric current is passed through. RF pulse generators are able to generate frictional heat in the surrounding tissue through ionic (Na + , K + and Cl − ) oscillating motion repeatedly in the presence of an electromagnetic field, which in turn causes thermal destruction of the nerves and interruption of the pain impulses [ 45 ]. Meanwhile, the use of fluoroscopic or ultrasonographic guidance could ensure smooth, painless, and precise introduction of the RF cannula into the joint.…”

Cooled radiofrequency ablation for pain related to Perthes’ disease: a novel application

“…This is done under fluoroscopy with a radiopaque marker located at the proximal end of the active tip. Standard RFA causes an elliptically shaped lesion with a size limited by the charred tissue acting as a significant insulator 13. In comparison, CRFA transmits radiofrequency waves through water-cooled electrodes, maintaining lower temperatures at the interface between the tip and tissue, enabling more radiofrequency energy to be delivered to the target nerves, creating lesions that are spherically shaped with a volume that is five times larger than standard RFA.…”

“…CRFA does this by targeting specific nerves that cause the pain, using heat to disrupt the pain pathways, much like performing a nerve block 23. Studies have reported that CRFA is clinically superior to other treatments for chronic knee pain such as intra-articular steroid or hyaluronic acid injections, where patients reported >65% pain relief lasting >12 months after receiving CRFA 13. Naber et al found that in 11 patients suffering from chronic hip pain from avascular necrosis, combined fluoroscopy and ultrasound-guided anterior CRFA of the lateral femoral and lateral obturator nerves resulted in a reduction in pain scores on the visual analogue scale from a mean of 7.6–2.3 with 5 patients reporting more than 50% pain relief from the CRFA 11.…”

MRI for in vivo Analysis of Ablation Zones Formed by Cooled Radiofrequency Neurotomy to Treat Chronic Joint Pain Across Multiple Axial Spine Sites

“…Cooled radiofrequency ablation (CRFA) probes differ from standard RFA probes in that water circulated through the CRFA probe tip draws heat away from the tissue-tip interface to prevent tissue charring or desiccation, which have been shown to greatly increase resistance to further energy flow. 5 CRFA probes deliver more energy than standard RF probes and form larger, more spherical ablation zones. It is believed that larger lesions can increase the chances of interventional success, as larger lesions improve the odds of successful capture of the target nerve within the lesion zone.…”