Temperature-Mediated Neural Interventions in Knee Osteoarthritis: a Review of Cryoneurolysis and Cooled Radiofrequency Ablation with Ultrasound Guidance.

PURPOSE OF REVIEW: Knee osteoarthritis is a debilitating chronic disease affecting nearly half of the world's population at some point in their lives. Treatment of pain and loss of function associated with this disease has been limited. In this review, we seek to explore how neural interventions with ultrasound guidance may be an emerging option for non-pharmacologic pain relief in patients with knee osteoarthritis. RECENT FINDINGS: Cryoneurolysis techniques have been demonstrated to provide pain relief out to 150 days post-treatment in knee osteoarthritis in select individuals. There have also been studies of cryoneurolysis pre-operatively to total knee replacement providing reduced pain, reduced opioid use post-operatively, and shorter hospital length of stay. Cooled radiofrequency ablation (CRFA) has been demonstrated to significantly reduce pain, improve functionality, and reduce pharmacologic needs in knee osteoarthritis out to 2 years. Both interventions appear to have increased accuracy with ultrasound, and CRFA appears to be associated with improved patient outcomes. The research demonstrates the efficacy of both cryoneurolysis and cooled radiofrequency ablation in the treatment of knee osteoarthritis. Ultrasound guidance in neurolysis provides an additional tool with real-time, high-accuracy nerve localization. These therapies should be considered for certain patients to assist in pain management in the non-operative and post-operative phase of knee osteoarthritis management. Further research is needed to further define the long-term effects and the long-term utility of the techniques in knee pain.

Cooled radiofrequency ablation of the sacroiliac joint a retrospective case series.

BACKGROUND: Sacroiliac (SI) joint dysfunction is a common source of back pain. Recent evidence from different parts of the world suggest that cooled radiofrequency ablation of sacral nerves supplying the SI joints has superior pain alleviating properties than currently available treatment options for SI joint dysfunction. PATIENTS AND METHODS: After obtaining institutional review board approval, the medical records of 81 patients who underwent cooled radiofrequency ablation in a single institution and by a single surgeon were analyzed retrospectively. The recurrence of pain, progression to fusion and functional outcomes were noted. The patients were operated on between June 2020 and December 2021, they include 59 females and 22 males, the average age was 55.4 ± 17.3. Follow up was at least 6 months postoperative. RESULTS: 22 of the patients had previously underwent lumbar fusions. Follow up period ranged from 6 to 18 months. After radiofrequency ablation, 7 patients progressed to fusions, and 6 patients had to have the procedure done again to relieve their pain. Student t-test was used to compare between preoperative and postoperative values of NPRS (numerical pain rating score) and ODI (Oswestry disability index). It showed significance with P-value < 0.001 in both. CONCLUSIONS: Sacroiliac joint radiofrequency ablation is a good option in the treatment of SI joint pain showing good results in the short term follow up period. It is a simple procedure that can be done in less than 30 min and is capable of providing significant pain relief for patients with sacroiliac joint dysfunction.

Cooled Radiofrequency Ablation of the Trochanteric Branch of the Nervus Femoralis to Treat Greater Trochanteric Pain Syndrome.

OBJECTIVE: Greater trochanteric pain syndrome is a common cause of lateral hip pain. Corticosteroid injections are commonly utilized as nonsurgical interventions; however, they are not effective for all patients. This technical case report describes a method for treating greater trochanteric pain syndrome by utilizing cooled radiofrequency ablation. METHODS: The trochanteric branch of the nervus femoralis is identified as providing sensory innervation to the greater trochanter and its surrounding structures. We have identified fluoroscopic targets to block the nerve and perform cooled radiofrequency ablation. We present two patient cases which demonstrated significant pain relief of greater trochanteric pain syndrome with this treatment. CONCLUSIONS: Cooled radiofrequency ablation of the trochanteric branch of the nervus femoralis is a potential treatment for greater trochanteric pain syndrome. This procedure provides a potential steroid-sparing interventional treatment based on reproducible fluoroscopic landmarks.

Cooled radiofrequency ablation of genicular nerves provides 24-Month durability in the management of osteoarthritic knee pain: Outcomes from a prospective, multicenter, randomized trial.

OBJECTIVE: To assess long-term outcomes of cooled radiofrequency ablation (CRFA) of genicular nerves for chronic knee pain due to osteoarthritis (OA). METHODS: A prospective, observational extension of a randomized, controlled trial was conducted on adults randomized to CRFA. Subjects were part of a 12-month clinical trial comparing CRFA of genicular nerves to a single hyaluronic injection for treatment of chronic OA knee pain, who then agreed to visits at 18- and 24-months post CRFA and had not undergone another knee procedure since. The subjects were evaluated for pain using the Numeric Rating Scale (NRS) function using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), subjective benefit using the Global Perceived Effect (GPE) scale, quality of life using the EuroQol-5-Dimensions-5 Level (EQ-5D-5L) questionnaire, and safety. RESULTS: Of 57 subjects eligible, 36 enrolled; 32 completed the 18-month visit with a mean NRS score of 2.4 and 22 (69%) reporting ≥50% reduction in pain from baseline (primary endpoint); 27 completed the 24-month visit, with a mean NRS of 3.4 and 17 (63%) reporting ≥50% pain relief. Functional and quality of life improvements persisted similarly, with mean changes from baseline of 53.5% and 34.9% in WOMAC total scores, and 24.8% and 10.7% in EQ-5D-5L Index scores, at 18- and 24-months, respectively. There were no identified safety concerns in this patient cohort. CONCLUSION: In this subset of subjects, CRFA of genicular nerves provided durable pain relief, improved function, and improved quality of life extending to 24 months post procedure, with no significant safety concerns.

Repeat Cooled Radiofrequency Ablation Is Beneficial for Chronic Posterior Sacroiliac Joint Pain.

OBJECTIVE: This study aimed to investigate the effectiveness of repeat cooled radiofrequency ablation (CRFA) in chronic posterior sacroiliac joint (SIJ) pain. DESIGN: The electronic records of 41 adult patients who had successful CRFA were reviewed for duration of pain relief and utilization of medical care for six months before and after each CRFA procedure. SETTING: Academic, tertiary medical center. PATIENTS: Forty-one adult patients who had CRFA for chronic posterior SIJ pain. RESULTS: A repeat ipsilateral CRFA ablation procedure provided 9.0 months of pain relief compared with 5.5 months after the first CRFA procedure (P = 0.0378). The total number of medical treatments decreased after the first CRFA procedure (from 343 to 201). The medical cost decreased by 51.0% after the first CRFA and by 70.4% after the repeated CRFA procedure. CONCLUSIONS: Using repeated nonsurgical, minimally invasive approach, CRFA relieves chronic posterior SIJ pain and reduces patients' utilization of medical services.

Twelve-Month Follow-Up of a Randomized Trial Assessing Cooled Radiofrequency Denervation as a Treatment for Sacroiliac Region Pain.

OBJECTIVE: The objective of this study was to report the long-term outcomes of cooled radiofrequency (CRF) lateral branch neurotomy (LBN) as a treatment for sacroiliac (SI) region pain. Whereas the 1-, 3-, 6-, and 9-month outcomes of this procedure compared to sham treatment were previously reported, this current report shows the 12-month outcomes of CRF/LBN treatment for SI region pain. DESIGN: This study originally included 51 subjects who were randomized 2:1 to receive CRF/LBN treatment or a sham intervention, respectively, for SI region pain. Subjects and assessors were blinded for 3 months. At that time, sham participants were permitted to receive CRF/LBN, designated as "crossover" study subjects, and followed for 6 additional months. For the purpose of this evaluation, the original CRF/LBN-treated study subjects were followed for a total of 12 months. Study participants were 18 to 88 years of age and had chronic (symptomatic for >6 months) axial back pain. All subjects were qualified for study inclusion following positive responses to dual lateral branch blocks. Lateral branch neurotomy was performed by CRF to ablate the S1 to S3 lateral branches and the L5 dorsal ramus. Pain was measured by a numerical rating scale (NRS) and Short Form 36-bodily pain (SF36-BP) scores. The Oswestry disability index and Short Form 36-physical functioning (SF36-PF) assessment each served to evaluate subject disability. Treatment successes ("responders") in the originally treated CRF/LBN group at 12 months, and in the crossover group at 6 months, were also determined. RESULTS: In the original CRF/LBN treatment group, 12-month outcomes compared to baseline were favorable, with a mean 2.7 point drop in the NRS score, a 13.9 decrease in the ODI, and a 15.8 increase in SF-36BP. In the crossover study group, 6-month outcomes were also favorable, with a mean NRS score decrease of 2.5 points, a reduction in ODI of 8.8, and an increase in SF36-BP of 11.9. CONCLUSIONS: These favorable 12-month results illustrate the durability of effective CRF/LBN-mediated treatment of SI region pain for selected patients. Furthermore, successful CRF/LBN treatments in unblinded crossover study subjects demonstrate the unlikelihood that such positive outcomes are attributable to a "placebo" effect, and suggest that CRF/LBN is an effective therapeutic option for alleviating pain, and improving physical function and quality of life, with few complications.

Incidence of neuropathic pain after cooled radiofrequency ablation of sacral lateral branch nerves.

OBJECTIVE: To determine the incidence of neuropathic pain after cooled radiofrequency ablation (RFA) of the sacral lateral branches for the treatment of chronic posterior sacroiliac joint complex pain. DESIGN: Retrospective chart review of all patients with chronic posterior sacroiliac joint complex pain who underwent cooled RFA of the sacral lateral branches in our practice between July 2011 and February 2014. SETTING: Single academic pain practice at a tertiary care medical center. SUBJECTS: Thirty-six patients with chronic posterior sacroiliac joint complex pain. METHODS: All charts were reviewed to determine the procedure date, unilateral or bilateral, number of levels treated, and number of individual lesions. Side effects were assessed for their presence or absence, character, intensity, duration, and whether treatment was initiated or symptoms resolved spontaneously. RESULTS: Forty-eight separate procedures were performed, with a total of 193 levels and 430 lesions. Three patients had transient postprocedure neuropathic pain yielding a 0.7% (95% confidence interval [CI]± 0.4%) rate of this complication per lesion. This proportion increases to 6.2% (95% CI ± 3.5%) per procedure and to 9.4% (95% CI ± 5.2%) per patient. CONCLUSION: The incidence of postprocedural neuropathic pain after cooled RFA for posterior sacroiliac joint complex denervation is low and in a similar range to that in the lumbar spine. We consider this procedure safe to be utilized by pain medicine practitioners.

Third-degree burn from cooled radiofrequency ablation of medial branch nerves for treatment of thoracic facet syndrome.

Radiofrequency ablation of medial branch nerves is considered a safe and effective treatment for chronic facet joint pain in the cervical, thoracic, and lumbosacral spine. Cooled radiofrequency ablation (C-RFA) is gaining popularity over conventional thermal radiofrequency ablation (RFA) in pain management. However, complications of C-RFA have not been reported in the literature. We present a first report of third-degree skin burn resulting from C-RFA electrode use for the treatment of facet syndrome. A 61-year-old woman (BMI of 21.8 kg/m(2) ) with thoracic facet syndrome underwent C-RFA of the T1-4 medial branch nerves (Thoracool System, Baylis Medical Company, Montreal, QC, Canada). Lesioning at the superior-lateral aspect of the thoracic transverse processes at each level was performed. During lesioning of the T2 MBN on the T3 transverse process, skin blanching 15 mm in diameter was noted around the introducer needle with patient complaints of severe, localized pain. Postprocedurally the skin injury at this level worsened in appearance, with a 20 mm × 4 mm skin defect, which took nearly 5 months to heal. With C-RFA, internally cooled electrodes are capable of creating large volume spherical lesions, a size advantage over conventional RFA. Although C-RFA lesion size may overcome the anatomic variability of target nerve location and potentially improve pain outcomes, added vigilance is required in thin patients and in anatomic regions of minimal subcutaneous tissue between the lesion target and the dermis. Skin burns at the site of the RF electrode are a potential risk under such conditions.

Efficacy of Cooled-Radiofrequency Ablation of the Genicular Nerve as Treatment for Chronic Knee Pain: A Retrospective Study.

INTRODUCTION: Chronic pain is one of the leading causes of reduced quality of life in the USA, with knee pain commonly reported. Multiple therapeutic modalities are traditionally utilized for pain management; however, some patients may have pain refractory to these techniques. Cooled radiofrequency ablation (c-RFA) of the geniculate nerve is a growing and promising therapy offering a potentially long-term solution to chronic knee pain. METHODS: This study assessed the efficacy, average duration of relief, and potential adverse events using a retrospective chart review of 406 procedures. A two-tailed paired t test was used to assess the statistical significance between pre-RFA vs. post-RFA visual analog scale (VAS) pain scores self-reported by patients. An analysis of variance (ANOVA) test was used to evaluate for statistical differences in pre-RFA pain scores and post-RFA pain scores among the categories of age, sex, body mass index (BMI), and diagnosis group. RESULTS: The mean percent in pain improvement calculated was 65.5% with an average duration of relief of 7.20 months. The average pre-RFA pain score on the VAS was 6.26 out of 10 and 2.59 out of 10 post-RFA. The ANOVA post-RFA pain scores demonstrated statistically significant differences among the categories of age and sex. A total of 54 adverse events were reported, including worsening pain, numbness, paresthesia, and knee swelling. CONCLUSION: The study demonstrated that c-RFA can potentially be utilized as an alternative safe therapy for chronic knee pain, providing pain relief with a relatively prolonged duration. Inherent challenges of retrospective studies remain a part of the limitations of this study.

Efficacy and Safety of Cryoablation Compared with Cooled Radiofrequency Ablation of Genicular Nerves in Advanced Osteoarthritis of the Knee: A Study Protocol of Single-Centric, Assessor-Blinded, Randomized, Parallel-Group, Non-inferiority Study.

PURPOSE: In patients with symptomatic osteoarthritis knee (OAK), cryoneurolysis (CRYO) and cooled radiofrequency ablation (C-RFA) are reported to be effective and safe; however, they have not been compared directly. The objective of this study is to compare CRYO and C-RFA of the genicular nerve (GN) in terms of efficacy and safety profile in patients with Kellgren and Lawrence (KL) grade ≥ 3 OAK. METHODS: This single-centric, assessor-blinded, randomized, parallel-group, non-inferiority study will include 80 patients with KL grade ≥ 3 OAK. The patients with ≥ 50% pain relief on diagnostic block of three GNs will be randomized to one of the two groups, i.e., CRYO (n = 40) or C-RFA (n = 40). The three target GNs for the interventions will include: superior medial, superior lateral, and inferior medial. The primary outcome will be efficacy of CRYO or C-RFA at 2, 12, and 24 weeks post-procedure based on the 11-point Numerical Pain Rating Scale. The secondary outcomes will be functional improvement based on 12-item Oxford Knee Score and safety of both the procedures. The study is registered in the Clinical Trials Registry-India. CONCLUSION: CRYO and C-RFA provide pain relief and improve functional outcome by preventing transmission of pain signals, though by distinct mechanisms. While C-RFA is an established treatment modality, recent evidence supports CRYO in patients with OAK. This study intends to demonstrate non-inferiority of CRYO against C-RFA, thereby supporting the use of CRYO as an additional treatment modality in patients with KL grade ≥ 3 OAK.

Traditional versus cooled-radiofrequency neurotomy for the treatment of chronic lumbar facet (zygapophyseal) joint pain.

Aim: Traditional radiofrequency ablation (TRFA) effectively treats facet joint-related pain, while water-cooled radiofrequency ablation (CRFA) may offer benefits like larger lesions and easier nerve access. Our goal is to assess the effectiveness of TRFA and CRFA for facet joint-related pain.Materials & methods: This retrospective study included an evaluation of 346 RFA interventions performed on 190 patients suffering from long-term low-back pain. The primary outcome was defined as a decrease of ≥50% of the mean numeric rating scale.Results: The primary outcome was achieved at the first follow-up (FU) for both TRFA and CRFA, with pain relief of 55.2 and 60.5%, respectively. At the second FU, the primary outcome was achieved only in the CRFA group (54.1%), although the TRFA group also showed a good improvement (48.6%). In both groups, pain relief was under 50% during the third FU.Conclusion: Our study indicates that both CRFA and TRFA modalities are effective and safe treatments.

What is this article about? In this study, the effectiveness of two different techniques of facet radiofrequency neurotomy (TRFA and CRFA) is compared. The study involved patients with facet joint-related back pain who did not improve with regular treatments but showed positive results with diagnostic blocks. The pain levels are recorded before and after treatment using a numeric rating scale at various times. The main goal was to see if pain decreased by 50% or more after the treatment. Second, the duration of time until patients need another treatment is investigated.What were the results? Both TRFA and CRFA reduced pain significantly in the first 4­8 weeks. TRFA patients had a 55.2% pain reduction, and CRFA patients had a 60.5% reduction. By 2­6 months, only the CRFA group maintained a 54.1% reduction, while the TRFA group had a 48.6% reduction. By 6­12 months, pain relief in both groups was found below 50%. Out of 81 treatments (44 TRFA and 37 CRFA), many patients needed another procedure within 6­12 months.What do the results of this study mean? Both TRFA and CRFA are effective and safe for treating chronic low back pain from facet joints. Although CRFA has some theoretical advantages over TRFA, the study found no significant difference in the outcomes between the two methods.

Cooled radiofrequency ablation of genicular nerves for knee osteoarthritis.

Knee osteoarthritis (OA) is a prevalent and debilitating musculoskeletal condition that significantly affects the quality of life of millions of individuals worldwide. In recent years, cooled radiofrequency ablation (CRFA) has become a viable treatment option for knee OA. This review thoroughly evaluated the existing literature on CRFA therapy for knee OA. It delved into the mechanisms behind CRFA, evaluated its clinical efficacy, and investigated potential avenues for future research and application. The insights gained from this review are crucial for healthcare professionals, researchers, and policymakers, offering an updated perspective on CRFA's role as a viable therapeutic option for knee OA.

Cooled radiofrequency ablation versus cryoneurolysis of the genicular nerves for the symptomatic pain management in knee osteoarthritis: a study protocol of a prospective, randomized, single-blinded clinical trial.

BACKGROUND: Cooled radiofrequency ablation (CRFA) and cryoneurolysis (CRYO) are two novel methods of genicular neurolysis to relief pain in symptomatic knee osteoarthritis (KOA). In this study, the two methods will be compared, giving us the opportunity to investigate their efficacy, safety and complications. METHODS: In this prospective randomized trial 70 patients with KOA will be recruited using a diagnostic block of four genicular nerves. Two groups will be created through software randomization: a CRFA group (35 patients) and a CRYO group (35 patients). The target of the interventions will be four genicular nerves; the superior medial, superior lateral, inferior medial, as well as the medial (retinacular) genicular branch from vastus intermedius. The primary outcome of this clinical trial will be the efficacy of CRFA or CRYO at 2-, 4-, 12-and 24-weeks post-intervention using the Numerical Rating Pain Scale (NRPS). The secondary outcomes are the safety of the two techniques, as well as the clinical evaluation using the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), and the 7-point scale of Patient Global Impression of Change (PGIC). DISCUSSION: These two novel techniques can block pain transmission through genicular nerves in different ways. In contrast to cryoneurolysis, the CRFA method has been well documented in the past. This is the first clinical trial to compare CRFA vs CRYO and draw conclusions about their safety and efficacy. TRIAL REGISTRATION: ISRCTN87455770 [ https://doi.org/10.1186/ISRCTN87455770 ]. Registered 29/3/2022, first patient recruited 31/8/2022.

Reducing opioid usage in total knee arthroplasty postoperative pain management: a literature review and future directions.

Total knee arthroplasty (TKA) is a common orthopedic surgery performed with a projected 3.5 million procedures to be done by 2030. Current postoperative pain management for TKA is insufficient, as it results in extensive opioid consumption and functional decline postoperatively. This study identifies the best practices for postoperative TKA pain management through a literature review of the last three years. Studies utilizing interventional techniques (local infiltration analgesia, nerve blocks) and pharmacologic options were reviewed on PubMed, Embase, Ovid Medline and Scopus. Primary outcomes analyzed were the effect of different analgesic approaches on pain reduction, opioid use reduction and improvements in functional mobility or quadriceps strength postoperatively. Additionally, this paper explores the use of cooled radiofrequency ablation, a minimally invasive therapy, for preoperative and postoperative TKA pain management.

Lay abstract Total knee arthroplasty (TKA), also known as 'knee replacement', is a common orthopedic surgery performed with a projected 3.5 million procedures to be done by 2030. Historically, pain management after TKA has involved opioids, but in light of recent extensive opioid dependence and consumption, pain management plans that incorporate other non-opioid techniques should be considered. This study identifies the best practices for postoperative TKA pain management through a literature review of the last 3 years. Studies utilizing interventional techniques such as local analgesia and nerve blocks, as well as pharmacologic options (involving the administration of medicines), were reviewed on the following databases: PubMed, Embase, Ovid Medline and Scopus. The main outcomes analyzed were the effect of these different approaches on pain reduction, opioid use reduction and improvements in functional mobility or strength of the quadriceps muscle in the thigh following TKA surgery. Additionally, this paper explores the use of cooled radiofrequency ablation, a minimally invasive therapy, for preoperative and postoperative TKA pain management.

IonicRF™: a novel step in technology for radiofrequency ablation treatments.

Radiofrequency ablation (RFA) has been utilized since the 1970s to treat various painful conditions. The technology has evolved from its initial use to treat lumbar facet mediated pain with monopolar lesioning to now treat a plethora of chronic pain conditions. This article reviews Abbott Corporation's (IL, USA) IonicRF™ generator. The IonicRF generator utilizes an intelligent power algorithm that improves efficiency and reduces procedure time. The generator also carries a wide range of RFA therapies such as monopolar, bipolar, pulsed or pulsed dose radiofrequency. Additionally, the IonicRF RFA generator is compatible with the Simplicity™ RF probe (Abbott) which allows for efficient and effective denervation of the sacroiliac joint.

Lay abstract Radiofrequency ablation (RFA) has been utilized since the 1970s to treat many different painful conditions. The technique was originally developed to treat common low back pain because of arthritis. Since that time, RFA has evolved to treat other painful areas of the body such as the face, knees, shoulders, hips and buttocks. RFA is a safe, convenient, and non-surgical option to treat pain in these different areas of the body. This technique is reserved for patients who have already tried physical therapy and over the counter pain medications such as ibuprofen and acetaminophen.

Clinical Outcome of Cooled Radiofrequency Ablation in Chronic Knee Pain Osteoarthritis: An Initial Experience from Nepal.

BACKGROUND: Cooled Radiofrequency ablation is a newer technique for management of chronic knee pain in osteoarthritis. The aim of the study is to evaluate the clinical outcomes in patients with chronic osteoarthritis in terms of pain scores for first six months of cooled radiofrequency ablation using ultrasound guidance. METHODS: A cross-sectional study with retrospective review of database was evaluated to analyze the change in the Numerical Rating Scale from baseline scores at 1 day, 1 month and 6 months after the Cooled Radiofrequency ablation of genicular nerves around knee in patients with chronic knee osteoarthritis. RESULTS: Median age was 71 years [ 61-73 years (IQR: 25-75)] with more female preponderance. Numerical Rating Scale (Mean ± S.D.) was significantly less at 1 day (1.87 ± 1.22), 1 month (3.03 ± 0.99) and 6 months (3.37 ± 1.098) from baseline values (6.77 ± 1.00). No soreness and numbness were noted. CONCLUSIONS: Cooled Radiofrequency using Ultrasound guidance for management of knee pain in chronic osteoarthritis is promising and reduces Numerical Rating Score significantly from baseline at 1 month and 6 months respectively.

Ultrasound-guided cooled radiofrequency ablation of the genicular nerves: a technique paper.

Aim: Cooled radiofrequency ablation (CRFA) has demonstrated efficacy in the management of knee pain caused by osteoarthritis. A typical procedure involves fluoroscopic placement of internally cooled radiofrequency probes to ensure the probes are located near target genicular nerves. Patients & methods: A new technique was developed to perform CRFA using ultrasound (US) guidance. Patient outcomes were reported using a telephone survey. Results: Ablation procedures were successfully performed using US guidance. A total of 51 patients were retrospectively identified for telephone screening. A total of 22 patients completed the telephone questionnaire. There were no safety concerns identified and the majority of patients reported satisfactory outcomes. Conclusion: Patient outcomes demonstrate that US-guided CRFA procedures provide pain relief and functional improvement. Further studies are needed to compare the efficacy of US-guided CRFA to fluoroscopy-guided CRFA procedures.

A technological overview of cooled radiofrequency ablation and its effectiveness in the management of chronic knee pain.

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.

Incidence and Clinical Significance of Cerebral Embolism During Atrial Fibrillation Ablation With Duty-Cycled Phased-Radiofrequency Versus Cooled-Radiofrequency: A Randomized Controlled Trial.

OBJECTIVES: The purpose of this study was to randomly compare the incidence of asymptomatic cerebral embolism (ACE) between the second-generation pulmonary vein ablation catheter (PVAC Gold) and the irrigated Thermocool catheter. BACKGROUND: Pulmonary vein isolation (PVI) with the PVAC is associated with ACE. The PVAC Gold was designed to avoid this complication. METHODS: Patients with paroxysmal atrial fibrillation were randomized 1:1 to PVI with the PVAC Gold or Thermocool catheter. Cerebral magnetic resonance imaging was performed in the days before and after ablation and repeated after 3 months in case of a new lesion. Monitoring for microembolic signals (MES) was performed by using transcranial Doppler ultrasonography. Parameters of coagulation were determined before, during, and after ablation. Neuropsychological tests and questionnaires were applied 10 days before and 3 months after ablation. RESULTS: Seventy patients were included in the study (mean age 61 ± 9 years; 43 male subjects; CHA2DS2-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score 1.6 ± 1.2; international normalized ratio 2.7 ± 0.5; activated clotting time 374 ± 24 s; p > 0.05 for all parameters). Procedural duration was shorter in the PVAC Gold group (140 ± 34 vs. 207 ± 44 min; p < 0.001). Eight (23%; 7 infarcts) patients in the PVAC Gold group exhibited a new ACE, compared with 2 (6%; no infarcts) patients in the Thermocool group (p = 0.042). Median number of MES was higher in the PVAC Gold group (1,111 [interquartile range, 715-2,234] vs. 787 [interquartile range, 532-1,053]; p < 0.001). There were no differences between groups regarding coagulation and neuropsychological outcomes. CONCLUSIONS: PVI with the new PVAC Gold was associated with a higher incidence of ACE/cerebral infarcts and number of MES. Both catheters induced a comparable procoagulant state. Because there were no measurable differences in neuropsychological status, the clinical significance of ACE remains unclear. (Cerebral Embolism [CE] in Catheter Ablation of Atrial Fibrillation [AF] [CE-AF]; NCT01361295).