This study is designed to:

• Determine the effectiveness (primarily measured by pain relief) of Coolief when used to create radiofrequency lesions of the genicular nerves compared to pain relief following corticosteroid injection; and
• Confirm the safety of Coolief when used to perform radiofrequency lesions of the genicular nerves in subjects to manage knee pain compared to safety of corticosteroid injection

This is a prospective, randomized, multicenter comparison study examining the outcomes of subjects having knee pain undergoing a procedure to create a radiofrequency lesion of the genicular nerves with the Coolief system compared to subjects receiving corticosteroid injection. A total of approximately 144 subjects will be enrolled into this study with subjects undergoing either radiofrequency neurotomy or corticosteroid injection in a 1:1 randomization scheme. Follow up will be conducted for a total of 12 months post Coolief procedure with the primary endpoint being completed at month 6. Subjects randomized to the comparison (corticosteroid) group will have the option to cross over to the neurotomy group after completing the 6 month endpoint assessment. They would then be followed for an additional 6 months. Pain, overall outcome, quality of life, pain medication use, and adverse events will be compared between the two treatment groups in order to determine success.

Primary Effectiveness Endpoint:

The proportion of subjects whose knee pain is reduced by ≥ 50% based on the NRS scale at 6 Months.

Primary Safety Endpoint:

The proportion of subjects experiencing adverse events through final follow up.

Secondary Effectiveness Endpoints:

• The proportion of subjects whose knee pain is reduced from baseline by ≥ 50% based on the Numeric Rating Scale (NRS) at 12 months.
• Improvement in global outcome from baseline as measured by the Oxford Knee Score at 6 months and 12 months.

Tertiary Effectiveness Endpoint:

Subject satisfaction as measured by the Global Perceived Effect Score at 6 months and 12 months.

Quaternary Effectiveness Endpoint:

Reduction in pain medication usage from baseline as measured by subject self-reported average daily dosage.

In addition, exploratory analyses of health economic indicators may be performed.

Subjects will participate in the study for up to 13 months (2 week roll-in period + treatment visit + 12 month follow up), except for subjects who participate in the optional crossover group. These crossover subjects will be on study for up to 15 months (2 week roll-in + treatment + 6 month follow-up and crossover + 6 month follow up). Enrollment is anticipated to take approximately 6-8 months.

INCLUSION CRITERIA

1. Age ≥ 21 years
2. Able to understand the informed consent form and provide written informed consent and able to complete outcome measures
3. History of chronic knee pain for longer than 6 months unresponsive to conservative treatments (PT, oral analgesics, intra-articular injections with steroids and/or viscosupplementation)
4. Positive response (defined as a decrease in numeric pain scores of at least 50%) to a geniculate nerve block of the index knee
5. Pain on NRS ≥ 6 on a 10 point scale for the index knee
6. Radiologic confirmation of osteoarthritis (x-ray/MRI/CT) of OA grade of 2 (mild), 3 (moderate) or 4 (severe) noted within 12 months for the index knee
7. Oxford Knee Score group at Baseline of ≤ 35 indicating moderate to severe OA in the index knee
8. If the patient is taking an opioid or other morphine equivalent medication, the dose must be considered clinically stable (defined as <10% change in dosage for ≥ 2 months prior to the screening visit).
9. Analgesics including membrane stabilizers such as Neurontin and antidepressants for pain such as Cymbalta must be clinically stable (defined as stable dosage for ≥ 6 weeks prior to the screening visit) and shall not change during the course of the study without approval of investigator. Agree to see one pain doctor (study investigator) for knee pain during the study period
10. Index knee pathology that is consistent with generally accepted indications for total knee arthroplasty.
11. Willing to delay any surgical intervention for the index knee for 12 months.
12. Willingness to provide informed consent and to comply with the requirements of this protocol for the full duration.

EXCLUSION CRITERIA

1. Pseudo arthritis, rheumatoid arthritis or other systemic inflammatory arthritis condition that could cause knee pain.
2. Previous or pending lower limb amputation.
3. Intra-articular steroid, platelet rich plasma (PRP) or hyaluronic acid injections in the index knee within 90 days from the screening visit.
4. An intra-articular corticosteroid injection is not indicated as an appropriate treatment option.
5. Prior radiofrequency of the genicular nerves of the index knee.
6. Prior partial, resurfacing, or total knee arthroplasty in index knee.
7. Clinically significant ligamentous laxity of the index knee.
8. Evidence of structural abnormality other than osteoarthritis of knee, hip or back that materially affects gait or function of the knee or is the underlying cause of the knee pain.
9. BMI > 40.
10. Extremely thin patients and those with minimal subcutaneous tissue thickness that would not accommodate a lesion of up to 14 mm in diameter to limit the risk of skin burns.
11. Pending or active compensation claim, litigation or disability remuneration (secondary gain) related to knee.
12. Pregnant or intent of becoming pregnant during the study period.
13. Chronic pain associated with significant psychosocial dysfunction.
14. Beck's Depression Index score of > 22 (indicates clinically depressed state).
15. Allergies to any of the medications to be used during the procedure.
16. Systemic or localized infection at needle entry sites (subject may be considered for inclusion once infection is resolved).
17. History of uncontrolled coagulopathy, ongoing coagulation treatment or unexplained or uncontrollable bleeding that is uncorrectable.
18. Identifiable anatomical variability that would materially alter the procedure as described in the protocol.
19. Within the preceding 2 years, subject has suffered from active narcotic addiction, substance or alcohol abuse.
20. Current prescribed opioid medications equivalent to greater than 60 morphine equivalent daily opioid dose.
21. Uncontrolled immunosuppression (e.g. AIDS, cancer, diabetes, etc.)
22. Subject currently implanted with pacemaker or defibrillator.
23. Participating in another clinical trial/investigation within 30 days prior to signing informed consent.
24. Subject unwilling or unable to comply with follow up schedule or protocol requirements.