This study is intended to prove the efficacy and safety of ultrasound-guided pulsed radiofrequency therapy on adductor canal nerves by patients with Knee osteoarthritis.

Knee osteoarthritis is a serious epidemiologic problem. Non-surgical methods are shown limited efficacy in relieving chronic knee pain in patients in advanced stages of knee osteoarthritis. The knee prosthesis is a successful treatment for many patients with advanced knee osteoarthritis. Still, there are important numbers of patients, which are not appropriate candidates for such surgery treatment or refused surgery for any reason. For them, any treatment which could relieve pain in their knee would have a good impact on their quality of life. Interventions like adductor canal block(ACB) and pulsed radiofrequency therapy (PRF) have demonstrated good results. In this study, investigators compare the effectiveness of these two methods. Official approval from the ethics committee of the Republic of Slovenia was obtained for this study. After being informed about the research and potential risks, all patients giving written informed consent will undergo an orthopedic examination and those with a confirmed diagnosis of knee osteoarthritis that lasted more than 6 months will be included in the study. All participants were randomly divided into two groups. Participants in the first group receive single shot ACB and participants in the second group receive PRF therapy at the same point. Before starting all patients filled the Knee injury and osteoarthritis outcome(KOOS) form and estimated the maximal and minimal intensity of pain in the knee. They repeat self-assessment of pain, in the same manner, using 11 points numeric rating score(NRS) 1 month, 3, and six months after the blockade or PRF therapy. Measurement of maximum voluntary isometric contraction of the quadriceps muscle (MVIC), time up and go test(TUG), and 30s stand-up chair test are performed by a physiotherapist before a block of adductor canal on both legs,1 hour, 1 month, 3 months and 6 months after a block or PRF therapy.The adductor canal blockl is performed by the same trained anesthesiologist at the proximal part of the leg using 14 ml of Levobupivacaine and 100 mcg of Clonidine mixed in the same syringeAfterof the study participants filled the Knee injury and osteoarthritis outcome(KOOS) form once again.

Inclusion Criteria:

• Diagnose of the Knee osteoarthritis confirmed by orthopedic examination
• K-L grades 3 and 4
• A sufficient level of education to understand study procedures
• Be able to communicate with site personnel
• Age >45 years

Exclusion Criteria :

• Any cardiovascular, hepatic, or renal conditions that would compromise participation, in the opinion of the investigator
• Severe neurologic conditions interfere with a knee condition
• Narcotic dependent (opioid intake of more than 3 months and more than 30 mg of daily oral morphine equivalents)
• Coexisting severe hematological disorder or deranged coagulation parameters
• Psychiatric illnesses
• Allergy to any of the drugs used in the study
• Infection or malignancy at the site of the block
• Any active systemic infection
• Implanted electronic devices like spinal cord stimulators, cardiac pacemakers or similar

All participants included in this study were sent by family physicians to our Pain ambulance and all have already been diagnosed with knee osteoarthritis chronic pain. The diagnosis was confirmed by Orthopedist engaged in our study. Anesthesiologist decides if the patient is appropriate for the study.

All IPD that underlie results in a publication will be shared with all other researchers.

After the end of the study and the publishing results.

The request needs to be addressed to the principal investigator. It should come from an official address or from a student or researcher personally.