A double-blind placebo-controlled randomized clinical trial to evaluate the efficacy of magnetic resonance-guided focused ultrasound surgery (MRgFUS) in the treatment of pain caused by knee osteoarthritis (OA)

Osteoarthritis (OA) is a common, disabling, and costly disease, and the knee is one of the most affected joints. The predominant symptom is pain. Effective and lasting non-invasive treatment approaches are missing. MR-guided focused ultrasound surgery (MRgFUS) is a new minimally invasive technique which may represent a valid solution providing several advantages. The primary aim of this work will be to assess the efficacy of MRgFUS in the treatment of pain caused by knee OA in 80 patients candidate for arthroplasty in a prospective, randomized, double-blinded, placebo-controlled clinical trial. Different parameters related to pain, quality of life, function, and imaging will be collected and analyzed in a 12-month follow-up. The secondary aims will be focused on a) the evaluation of the effects on the joint organ and changes of biological features in response to MRgFUS, and b) the impact of selective ablation of nociceptors on OA pain, based on the analysis of resected joint tissues.

Inclusion Criteria:

• Male and female aged 50-80 years
• Activity-related joint pain
• Patients who have not responded to previous treatments and patients candidate for surgery
• Kellgren-Lawrence score 2-4 on X-rays
• Patients able to give their informed consent

Exclusion Criteria:

• Prior surgery in the past 12 months or previous local treatment in the past 3 months
• Changes in medications used during the previous 2 months
• Corticosteroid use for more than 3 months within the preceding year
• Rheumatologic and neurological disorders
• Fibromyalgia
• Trauma, fracture or osteomyelitis of the investigated joints within the preceding year
• Pregnancy
• Patients with large scars potentially included in the ultrasound beam path
• General contraindications to MRI and/or to anaesthesiological procedures
• Presence of internal hardware or device potentially affecting MR thermometry
• Patients involved in other clinical studies

Participating patients will be blinded to treatment assignment and to the ongoing results of the study; they will remain blinded to their assignment throughout the study period. All the staff involved in the pre- and post-treatment evaluation of patients will be also blinded. The evaluation of patients will be performed by physicians not involved in the treatment to ensure double blinding.