Genicular Artery Embolization Vs Observation for Symptomatic Knee Osteoarthritis

This is a single-center, prospective, open-label randomized trial to compare outcomes of GAE versus observation, and to identify biomarkers and imaging endpoints that change in response to GAE. Subjects will be considered enrolled in the study once they have provided informed consent and have been determined to meet all eligibility criteria. A total of 100 subjects will be enrolled in the double-arm study and will be followed for 24 months. The study will involve a screening period in which patient eligibility is determined. Once eligibility is confirmed, subjects will then be randomized to GAE or observation in a 2:1 ratio. Group sample sizes of 80 and 40 achieve approximately 85% power to reject the null hypothesis of no difference in the clinical response defined by 50% or greater reduction in WOMAC between the treatment and observation arms with a significance level (alpha) of 0.050 using a two-sided two-proportions using Fisher's exact test. With 120 symptomatic knee osteoarthritis subjects, the power of study is approximately 85% where we assume a target response rate of 67.5% for the experimental arm and 31% for the observational arm with up to 20% drop-out rate prior to 6 months. All study subjects will undergo the initial procedures, consisting of a history and physical exam, dynamic contrast-enhanced knee MRI, blood serum and joint aspiration with biochemical analysis. For the treatment arm, subjects will undergo GAE with Embozene microspheres (100 micron) (Varian Medical Systems). Observation group will not receive the GAE procedure at baseline, and will be counseled on conservative management with a referral or prescription for physical therapy. Follow-up visits will be at 1 month (± 2 weeks), 3 months (± 2 weeks), 6 months (± 2 weeks), 12 months (± 2 weeks), and 24 months (± 2 weeks) post-procedure. At these visits, subjects will complete the WOMAC, KOOS5, visual analog scale (VAS) pain score, undergo a directed physical examination, and report any new adverse events (AEs). At 6 and 24 months of follow-up, all subjects will also undergo dynamic contrast-enhanced knee MRI, and serum and joint aspiration with biochemical analysis. At 6 months, subjects in the observation group will have the option to crossover to the GAE treatment arm. Subjects in the crossover group will then undergo GAE, with follow up at 1 month (± 2 weeks), 3 months (± 2 weeks), 6 months (± 2 weeks), 12 months (± 2 weeks), and 24 months (± 2 weeks) post-GAE. For the purposes of data analyses, the follow-up evaluations for crossover subjects will match those of the initial GAE subjects. For example, if a subject in the observation arm undergoes GAE crossover at 6 months, that will be considered the treatment visit, and then subject will undergo evaluation at 1, 3, 6, 12, and 24 months after GAE.