Long-term outcomes of genicular artery embolization for knee osteoarthritis: 12-month efficacy and secondary outcomes from a randomized sham-controlled clinical trial

OBJECTIVES: To determine if genicular artery embolization (GAE) is more effective in relieving pain symptoms after 12 months compared to a sham procedure in patients with mild to moderate knee osteoarthritis. A secondary aim was to investigate changes in synovitis observed at 4 months and the correlation with other clinical outcomes. MATERIALS AND METHODS: A randomized controlled trial included patients with mild to moderate knee osteoarthritis unresponsive to conservative treatment, who were randomly assigned to receive either GAE or sham treatment. Follow-up was at 1, 4, 8, and 12 months. Pain was assessed using the Knee Injury and Osteoarthritis Outcome Score, and synovitis was imaged with contrast-enhanced MRI at baseline, 1, and 4 months. Outcomes were compared using generalized estimating equations. RESULTS: Fifty-eight patients were included (GAE group: 29, sham group: 29). Pain scores improved from 44.44 (95% CI: 38.87-50.02) at baseline to 65.61 (95% CI: 57.16-74.06) after 12 months in the GAE group and from 42.34 (95% CI: 36.45-48.22) to 58.15 (95% CI: 48.7-67.6) in the sham group. The between-group difference after 12 months was not significant (7.46; 95% CI: -13.63 to -28.56; p = 0.25). There were no significant within-group or between-group changes for synovitis. CONCLUSION: Patients undergoing GAE and sham GAE both demonstrate an equal sustained pain reduction at 12 months follow-up, with no differences in synovitis reduction or other clinical outcomes. These results suggest a sustained placebo effect in the long term and do not support the clinical implementation of GAE as a treatment for KOA patients. KEY POINTS: Question Is GAE more effective than a sham procedure for mild-to-moderate knee osteoarthritis in the long term, and how does it affect synovitis? Findings There was no significant difference in pain reduction or synovitis between the two groups. Clinical relevance Pain reduction after GAE appears mainly placebo-driven. The placebo effect is sustained up to 12 months. Furthermore, synovitis was unaffected by the procedure. Therefore, our findings do not support clinical implementation.