Radiofrequency ablation for the treatment of chronic pain after knee arthroplasty: protocol for a randomized, double-blind study

To date, there is no standard treatment for chronic pain after knee arthroplasty. Radiofrequency ablation of the sensory nerves in the knee has become a useful therapeutic approach; however, variability in terms of treatment approaches and anatomical targets causes difficulties in standardizing a reproducible and viable technique. The aim of this study is to determine if radiofrequency ablation of the nerves of the vastus medialis (NVM), vastus intermedius (NVI), vastus lateralis (NVL), and infrapatellar branch of the saphenous nerve (IPBSN) improves pain and disability from baseline to 3 months versus placebo in patients with post-knee arthroplasty pain. This double-blind, placebo-controlled, randomized trial will be conducted in two hospitals in Catalonia, Spain. Patients will undergo anaesthetic blocks of nerve branches to determine radiofrequency candidacy. After adequate response to the anaesthetic blocks (≤ 50% of baseline pain levels for > 24 h), patients will be subjected to radiofrequency ablations or control simulations. Treatment responses will be evaluated using clinically validated questionnaires (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC], visual numerical scale for pain, DN4 questionnaire for neuropathic pain, Hospital Anxiety and Depression Scale [HADS], Pain Catastrophizing Scale [PCS]). Follow-up outcome scores will be collected up to 12 weeks after radiofrequency ablation. The planned sample size is 86 patients. As of February 19, 2025, a total of 19 patients have been enrolled, and 12 have completed all study procedures. NCT05920382