From Bench to Bedside: Pain Relief is Cool.

Abstract

Osteoarthritis (OA) of the knee affects an estimated 14 million people in the United States alone [6], and while many of them achieve symptomatic relief without surgery, for others, it is a painful, lifestyle-limiting problem. Patients with severe or refractory symptoms often go on to request and receive TKA, which remains an extremely effective treatment option. Still, a large proportion of patients are left with persistent pain and functional limitations after this major intervention, and a smaller proportion experience severe complications. And, let’s face it, many patients are just plain frightened of surgery. Regardless of symptom severity, patients seeking to avoid (or who are poor medical candidates for) surgery may nonetheless continue to be in pain, decrease their activity levels, or develop progressive joint deformities. The problem with our approaches for managing patients with knee arthritis is that none of our techniques are risk free or effective for everyone. We thus continue to search for additional treatment tools for our symptommitigation toolbox. One such treatment approach involves, at least temporarily, disrupting the nociceptive signals from the knee itself. A recent multicenter randomized trial by Chen et al. [1] reported that cooled radiofrequency ablation (CRFA) produced a > 50% reduction in pain in 71% of those treated with CRFA of four genicular nerves versus only 38% of those treated with hyaluronic acid injection. Similar differences between cohorts were found in WOMAC (48.2% versus 22.6% improvement) and quality of life scores (Global Perceived Effect; 72% versus 40% reporting improvement) at 6-month follow-up [1]. This study had some limitations: the study population was carefully screened such that only patients reporting > 50% pain relief with a diagnostic block were even randomized, and viscosupplementation is not recommended by the American Academy of Orthopaedic Surgeons clinical practice