Due to financial constraints, sponsor could not complete the study.

This is a single center randomized controlled trial. Approximately 102 patients will be randomized to one of two treatment groups: cooled radiofrequency or conventional monopolar radiofrequency ablation. Patients with chronic knee pain, with moderate to severe osteoarthritis according to the Kellgren-Lawrence scale for at least 6 months who have failed conservative therapy will be screened for the study.

Then, patients will be enrolled based on reporting ≥50% pain relief after a fluoroscopic guided single diagnostic block of the geniculate nerves (superior medial, superior lateral, and inferior medial) with 0.5 ml of local anesthetic (2% Lidocaine).

Baseline data will be collected for all enrolled patients. Outcomes will be measured at 1, 4, 12, 24 and 52 weeks.

Outcome measures will be: Visual analogue scale (VAS) both while at rest and during ambulation, Oxford knee scores, WOMAC, and global perceived effect.

Inclusion Criteria:

• Patients who have given their written informed consent to participate in this clinical study based on voluntary agreement after a thorough explanation of the patient's participation is provided to them.
• Female patients who are not pregnant and do not plan to become pregnant during the study. Females of child bearing potential must provide a negative pregnancy test provided by the study physician and must be using reliable contraception and must continue to use reliable contraception until study completion at 52 weeks. Non-childbearing potential is defined as postmenopausal for at least 2 years or surgical sterilization or hysterectomy at least 3 months before study start.
• Must be older than 18 years old..
• Must have chronic knee pain for at least 6 months.
• Must have radiologic evidence of OA of the knee, grade 2-4 based on the Kellgreen-Lawrence scale.
• Persistent pain despite the use of conservative treatment (physical therapy, oral analgesic, steroid injections).
• Must have a VAS score of at least 5 with ambulation.
• Subjects must be on a stable dose of pain medication regimen for at least 2 months.
• Greater than or equal to 50% improvement from blocks in target knee for duration of the anesthetic.

Exclusion Criteria:

• Knee pain must not be acute.
• Previous total knee replacement.
• Evidence of connective tissue disease.
• Patients who have a BMI greater than 40.
• Evidence of serious neurological or psychiatric disorders.
• Current opioid use must not be greater than or equal to 90 mg morphine equivalent per 24 hour period.
• Must not have radicular pain in the affected limb.
• Patients with uncorrected coagulation disorders or who are on anticoagulation therapy and cannot interrupt the therapy.
• Patients who have pacemakers or generators.
• Patient who are pregnant, breast-feeding or women of childbearing potential with positive pregnancy tests.
• Sexually active female patients of childbearing potential who are not willing to use adequate contraceptive measures to avoid pregnancy until week 52 of the study. Sexually active male patients who are not willing to use adequate contraceptive measures until week 52 of the study. Adequate methods of birth control include the following: Hormonal contraception (female patients) or use of at least one acceptable double-barrier method (for example: diaphragm plus spermicidal agent or condoms (male or female) plus spermicidal agent.), vasectomy, intrauterine device, and/or exclusive sexual partner for whom one of the above acceptable methods applies.
• Patients who have cancer or a past history of any cancer within 5 years prior to the time of informed consent, with the exception of basal cell or squamous cell carcinoma of the skin.
• Human immunodeficiency virus (HIV) infection or a clinically significant infection.
• A clinically significant disorder such as cerebrovascular disease, pulmonary infarction, ischemic heart disease, cardiac dysrhythmia, myocardial infarction, or congestive heart failure.
• Uncontrolled diabetes, uncontrolled pulmonary disease, or uncontrolled hypertension.
• Patients who have evidence of major psychiatric disease, mental disorder, drug dependency, alcohol dependency, or substance abuse disorders.
• Any patient with a medical condition and/or disease that the Investigator believes could affect the study results or the safe conduct of the study.
• Patients who are receiving compensation according to Workers' Compensation Act or are involved in personal injury litigation.
• Patients who participated in another clinical study within 3 months prior to the time of informed consent, or who are expected to participate in another study during the period of this study.