The proportion of subjects whose knee pain is reduced by ≥ 50% based on the NRS. The NRS is an 11-point scale (0 points to 10 points), where 0 points equals "no pain" and 10 points equals the "worst pain". There are no sub-scales.

76 of the 89 originally-randomized study subjects in the Cooled Radiofrequency group completed this 6-month outcome. 82 of the originally-randomized 88 study subjects in the Hyaluronic Acid Injection group completed this 6-month outcome.

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

The proportion of subjects whose knee pain is reduced from baseline by ≥ 50% based on the NRS. The NRS is an 11-point scale (0 points to 10 points), where 0 points equals "no pain" and 10 points equals the "worst pain". There are no sub-scales.

66 of the 89 originally-randomized study subjects in the Cooled Radiofrequency group completed this 12-month outcome measure. 62 of the originally-randomized 88 study subjects in the Hyaluronic Acid Injection group chose to crossover to receive Cooled Radiofrequency treatment and completed this 12-month outcome. 11 of the originally-randomized subjects in this group who elected not to crossover completed this 12-month outcome.

The change in WOMAC score from baseline to 6 months. This outcome instrument is composed of three sub-scales, including "Pain" (5 questions), "Stiffness" (2 questions), and "Physical Function" (17 questions). The point range for each sub-scale question is from 0 to 4, with "0" indicating the best study subject condition and "4" indicating the worst study subject condition. Thus, the minimum score per sub-scale is 0, and the maximum is 20, 8, and 68 for "Pain", Stiffness", and "Physical Function", respectively. The minimum and maximum possible scores for the entire instrument are 0 (best study subject condition) and 96 (worst study subject condition).

The 'change from baseline' was unable to be calculated for one of the CRFA-randomized subjects as appropriate baseline measurements for this outcome measure were not collected. The comparison could not be performed for this subject. Therefore, the Overall Number of Participants Analyzed in this group is reduced by one.

The change in WOMAC score from baseline to 12 months. This outcome instrument is composed of three sub-scales, including "Pain" (5 questions), "Stiffness" (2 questions), and "Physical Function" (17 questions). The point range for each sub-scale question is from 0 to 4, with "0" indicating the best study subject condition and "4" indicating the worst study subject condition. Thus, the minimum score per sub-scale is 0, and the maximum is 20, 8, and 68 for "Pain", Stiffness", and "Physical Function", respectively. The minimum and maximum possible scores for the entire instrument are 0 (best study subject condition) and 96 (worst study subject condition).

The 'change from baseline' was unable to be calculated for one of the CRFA-randomized subjects as appropriate baseline measurements for this outcome measure were not collected. The comparison could not be performed for this subject. Therefore, the Overall Number of Participants Analyzed in this group is reduced by one.

The change in measured EQ-5D-5L scale from baseline to 6 months. This outcome instrument is composed of five sub-scales containing five questions each. The point range for each sub-scale is from 1 to 5, with "1" indicating the best study subject condition and "5" indicating the worst study subject condition. Thus, the minimum and maximum scores per sub-scale are 1 and 5, respectively, and such scores for the entire instrument are 5 (best study subject condition) and 25 (worst study subject condition). The sub-scale topics are: Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression.

The 'change from baseline' was unable to be calculated for one of the CRFA-randomized subjects as appropriate baseline measurements for this outcome measure were not collected. The comparison could not be performed for this subject. Therefore, the Overall Number of Participants Analyzed in this group is reduced by one.

The change in measured EQ-5D-5L scale from baseline to 12 months. This outcome instrument is composed of five sub-scales containing five questions each. The point range for each sub-scale is from 1 to 5, with "1" indicating the best study subject condition and "5" indicating the worst study subject condition. Thus, the minimum and maximum scores per sub-scale are 1 and 5, respectively, and such scores for the entire instrument are 5 (best study subject condition) and 25 (worst study subject condition). The sub-scale topics are: Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression.

The 'change from baseline' was unable to be calculated for one of the CRFA-randomized subjects as appropriate baseline measurements for this outcome measure were not collected. The comparison could not be performed for this subject. Therefore, the Overall Number of Participants Analyzed in this group is reduced by one.

Number of participants with improvement measured by the Global Perceived Effect scale. The Global Perceived Effect is a 7-point scale: 1 point = "worst ever", 2 points = "much worse", 3 points = "worse", 4 points = "not improved but not worse", 5 points = "improved", 6 points = "much improved", 7 points = "best ever". There are no sub-scales. Number of participants scoring at either 5, 6, or 7 points on the Global Perceived Effect scale are reported.

Number of participants with improvement measured by the Global Perceived Effect scale. The Global Perceived Effect is a 7-point scale: 1 point = "worst ever", 2 points = "much worse", 3 points = "worse", 4 points = "not improved but not worse", 5 points = "improved", 6 points = "much improved", 7 points = "best ever". There are no sub-scales. Number of participants scoring at either 5, 6, or 7 points on the Global Perceived Effect scale are reported.

The proportion of subjects whose knee pain is reduced from baseline by ≥ 50% based on the NRS. The NRS is an 11-point scale (0 points to 10 points), where 0 points equals "no pain" and 10 points equals the "worst pain". There are no sub-scales.

32 of the 36 study subjects who elected to participate in the CRFA extension phase of the study completed this 18-month outcome measure.

The proportion of subjects whose knee pain is reduced from baseline by ≥ 50% based on the NRS. The NRS is an 11-point scale (0 points to 10 points), where 0 points equals "no pain" and 10 points equals the "worst pain". There are no sub-scales.

27 of the 36 study subjects who elected to participate in the CRFA extension phase of the study completed this 24-month outcome measure.

The change in WOMAC score from baseline to 18 months. This outcome instrument is composed of three sub-scales, including "Pain" (5 questions), "Stiffness" (2 questions), and "Physical Function" (17 questions). The point range for each sub-scale question is from 0 to 4, with "0" indicating the best study subject condition and "4" indicating the worst study subject condition. Thus, the minimum score per sub-scale is 0, and the maximum is 20, 8, and 68 for "Pain", Stiffness", and "Physical Function", respectively. The minimum and maximum possible scores for the entire instrument are 0 (best study subject condition) and 96 (worst study subject condition).

Extension study subjects with 18-month data available for analysis for this outcome measure

The change in WOMAC score from baseline to 24 months. This outcome instrument is composed of three sub-scales, including "Pain" (5 questions), "Stiffness" (2 questions), and "Physical Function" (17 questions). The point range for each sub-scale question is from 0 to 4, with "0" indicating the best study subject condition and "4" indicating the worst study subject condition. Thus, the minimum score per sub-scale is 0, and the maximum is 20, 8, and 68 for "Pain", Stiffness", and "Physical Function", respectively. The minimum and maximum possible scores for the entire instrument are 0 (best study subject condition) and 96 (worst study subject condition).

Extension study subjects with 24-month data available for analysis for this outcome measure

The change in measured EQ-5D-5L scale from baseline to 18 months. This outcome instrument is composed of five sub-scales containing five questions each. The point range for each sub-scale is from 1 to 5, with "1" indicating the best study subject condition and "5" indicating the worst study subject condition. Thus, the minimum and maximum scores per sub-scale are 1 and 5, respectively, and such scores for the entire instrument are 5 (best study subject condition) and 25 (worst study subject condition). The sub-scale topics are: Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression.

Extension study subjects with 18-month data available for analysis for this outcome measure

The change in measured EQ-5D-5L scale from baseline to 24 months. This outcome instrument is composed of five sub-scales containing five questions each. The point range for each sub-scale is from 1 to 5, with "1" indicating the best study subject condition and "5" indicating the worst study subject condition. Thus, the minimum and maximum scores per sub-scale are 1 and 5, respectively, and such scores for the entire instrument are 5 (best study subject condition) and 25 (worst study subject condition). The sub-scale topics are: Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression.

Extension study subjects with 18-month data available for analysis for this outcome measure

Number of participants with improvement measured by the Global Perceived Effect scale. The Global Perceived Effect is a 7-point scale: 1 point = "worst ever", 2 points = "much worse", 3 points = "worse", 4 points = "not improved but not worse", 5 points = "improved", 6 points = "much improved", 7 points = "best ever". There are no sub-scales. Number of participants scoring at either 5, 6, or 7 points on the Global Perceived Effect scale are reported.

Extension study subjects with 18-month data available for analysis for this outcome measure

Number of participants with improvement measured by the Global Perceived Effect scale. The Global Perceived Effect is a 7-point scale: 1 point = "worst ever", 2 points = "much worse", 3 points = "worse", 4 points = "not improved but not worse", 5 points = "improved", 6 points = "much improved", 7 points = "best ever". There are no sub-scales. Number of participants scoring at either 5, 6, or 7 points on the Global Perceived Effect scale are reported.

Extension study subjects with 18-month data available for analysis for this outcome measure

Safety: The proportion of subjects experiencing adverse events between 12 - 24 months (Extension)