Cooled radiofrequency ablation versus cryoneurolysis for the symptomatic management of pain in knee osteoarthritis: a prospective, randomized, sham-controlled, double-blind trial
Relief of pain related to knee osteoarthritis
Approximately 400 patients with symptomatic knee OA visit the clinic each year. A small percentage has an end-stage disease, only amenable for total knee replacement. Most of the remaining patients require conservative measures initially to control their symptoms and from those patients a respectable percentage has not been able to respond to oral medications, physiotherapy, loss of weight and injectable therapies. This will be the pool of patients that will participate in this randomized trial. After establishing the diagnosis of knee arthritis according to the eligibility criteria outlined below, the patients will visit again the Department for diagnostic block (with lidocaine) of the genicular nerves, under ultrasound guidance. Patients would be only enrolled in the study if they report, at least a 50% reduction of their pain (as measured using the NRPS). Eligible patients will then be randomized 2:2:1 to either CRFA, CRYON or SHAMS. This will allow the researchers to test the clinical results of both CRFA and CRYON with the SHAMS group, but also between each other in terms of safety and complication rate. Patients will be placed in the operating theatre in a supine position with a bolster under the knee to produce 30 degrees of flexion. A sealed and opaque envelope will be brought to the operation theatre, dictating the group of each patient. The treated knee will be draped and sterilized in a standard manner; one dose of third-generation cephalosporin will be given for infection prophylaxis. Patients would be continuously monitored and given conscious sedation (1–2 mg IV and/or fentanyl (25–100 mcg IV)) and supplemental oxygen. The location of the nerves (SLGN, SMGN, IMGN and SPGN) will be identified with the use of ultrasound and/or fluoroscopy according to the standard described methods. The technique deployed to spot the genicular nerves and perform accurate ablation is the one presented by Lash et al. The US transducer is initially oriented in the coronal
Patients of either sex will participate in the clinical trial as long as they have: 1. The NICE clinical criteria of primary knee OA for one or both knees: 1.1. Age >45 years 1.2. Activity-related joint pain 1.3. No morning joint stiffness or morning stiffness that lasts no longer than 30 minutes 2. Radiological confirmation of knee arthritis (grade ≥2) according to the Kellgren and Lawrence classification 3. Chronic knee pain for a minimum duration of 6 months 4. Pain intensity ≥4 on the (NRPS) 5. A decrease of ≥50% in NRPS scores with diagnostic genicular nerve block 6. The ability to communicate in Greek
1. inflammatory or post-traumatic knee arthritis 2. Patients who have received CRYON or CRFA treatment in the past 3. Injection of hyaluronic acid or corticosteroid within the previous 3 months 4. Significant structural deformities affecting locomotion and knee function aside from osteoarthritis and which might cause chronic knee pain 5. Body mass index ≥40 kg/m² 6. Uncontrolled serious disease (cancer, diabetes, end-stage heart disease etc) 7. Unstable psychiatric illness 8. Coagulopathy or bleeding disorders 9. Active systemic or local infection 10. Disease-associated with reactions to cold, such as cryoglobulinemia