Comparison of Conventional and Cooled Radiofrequency Treatment of the Genicular Nerves Versus Sham Procedure for Patients With Chronic Knee Pain: a Multicentre, Double Blind, Randomised Controlled Trial
Chronic knee pain remains a disabling disease despite current treatment strategies. There is an increase in the prevalence of osteoarthritis (OA) of the knee in the general population, presently affecting approximately 450,000 individuals in Belgium. A total knee replacement is a viable alternative for severe knee OA that does not respond to conservative therapy. Unfortunately, up to 53% of patients who undergo a total knee replacement develop persistent post-surgical pain (PPSP). There is currently no effective therapy for PPSP. A radiofrequency (RF) treatment applies high frequency current on the nerve responsible for pain conduction, resulting in an interruption of the transmission of pain. This can be applied to the nerves innervating the knee joint - the superolateral, superomedial and inferomedial genicular nerves - and could be an alternative, minimally invasive treatment for patients with knee OA who fail conservative treatments and for patients with PPSP. Data from the recent literature indicates that this treatment leads to a reduction of pain intensity and could result in an improvement of knee function, of the psychological state of the individual, and finally in an increase in health-related quality of life. Furthermore, RF of the genicular nerves could help avoid or delay a total knee replacement therefore potentially contributing to cost reduction. Both cooled and conventional RF treatments are reported in the literature to improve pain. The use of water to cool the RF electrodes results in an increased lesion size by removing heat from adjacent tissue, allowing power delivery to be increased. As a consequence, cooled RF could result in a higher chance of success and longer duration of effect. Until now, the studies performed on cooled RF are industry initiated and a direct comparison between conventional, cooled and a sham procedure is lacking. The aim of the COGENIUS trial is to investigate the effect of the two types of RF treatment on individuals experiencing chronic knee pain that is resistant to conservative treatments. For this purpose, the efficacy and cost-effectiveness of cooled and conventional RF will be compared to a sham procedure in patients suffering from knee OA and PPSP after total knee replacement.
• Signed written informed consent must be obtained before any study assessment is performed.
• Adult patients (Age ≥ 18 years old).
• Chronic anterior knee pain (\> 12 months) that is moderate to severe (defined as NRS \> 4 on most or all days for the index knee either constantly or with motion at time of screening and, an average NRS score reported in the patient diary \>4 at the end of the run-in period).
• Unresponsive (meaning insufficient pain reduction or intolerance) to conventional treatments ongoing for at least 12 months prior to inclusion. Conventional treatments must include all of the following: active physiotherapy, pharmacological treatment of pain and intra-articular corticosteroid infiltration.
• Only for patients with Osteoarthritis (OA): Radiologic confirmation of knee osteoarthritis of grade 2 (mild), 3 (moderate) or 4 (severe) noted within 12 months prior to the screening for the index knee according the Kellgren Lawrence criteria diagnosed by an independent radiologist with experience in musculoskeletal imaging on radiography (Rx) or magnetic resonance imaging (MRI). If imaging will need to be performed at screening it is recommended to perform an MRI instead of Rx. Imaging with MRI will enable the independent radiologist to perform a better estimation of the grade of OA.
• Only for patients with Persistent Post-Surgical Pain (PPSP) after Total Knee Arthroplasty (TKA): Patients with PPSP\* after TKA need to have had a negative orthopaedic work-up