Midterm Clinical Outcomes and MR Imaging Changes after Transcatheter Arterial Embolization as a Treatment for Mild to Moderate Radiographic Knee Osteoarthritis Resistant to Conservative Treatment

Purpose: To describe the safety and efficacy of transcatheter arterial embolization for mild to moderate radiographic knee osteoarthritis (OA) that is resistant to conservative treatment. Materials and Methods: This prospective study included 72 patients (95 knees) with OA of Kellgren-Lawrence (KL) grade 1-3 and persisting moderate to severe pain that was resistant to conservative management who were treated with transcatheter arterial embolization between July 2012 and March 2016. Clinical outcomes were evaluated at 1, 4, and 6 months and then every 6 months for a maximum of 4 years. The Whole-Organ Magnetic Resonance Imaging Score (WORMS) was evaluated at baseline and at 2 years after embolization in 35 knees. Results: Abnormal neovessels were identified in all cases. There were no major adverse events related to the procedures. Mean Western Ontario and McMaster Universities Osteoarthritis Index pain scores significantly decreased from baseline to 1, 4, 6, 12, and 24 months after treatment (12.1 vs 6.2, 4.4, 3.7, 3.0, and 2.6; all P < .001). The cumulative clinical success rates at 6 months and 3 years after embolization were 86.3% (95% confidence interval [CI], 78%-92%) and 79.8% (95% CI, 69%-87%), respectively. WORMS scores at 2 years after embolization in 35 knees showed significant improvement of synovitis vs baseline (P = .0016) and no osteonecrosis or other evidence indicating aggressive progression of degenerative changes. Conclusions: Transcatheter arterial embolization significantly improved pain symptoms and clinical function in patients with mild to moderate knee OA that was resistant to conservative treatment.