Association between Baseline Osteoarthritic Features on MR Imaging and Clinical Outcome after Genicular Artery Embolization for Knee Osteoarthritis

Purpose: To explore the association between baseline osteoarthritis (OA)-related magnetic resonance (MR) imaging features and pain reduction after genicular artery embolization (GAE) in patients with mild-to-moderate symptomatic knee OA resistant to conservative therapy. Materials and Methods: This was a retrospective analysis of patients with mild-to-moderate symptomatic knee OA treated with GAE using imipenem-cilastatin sodium. The clinical outcome was scored at baseline and 6 months after treatment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). MR images were scored using the MR imaging osteoarthritis knee score. Linear regression was used to evaluate associations of before-treatment MR imaging scores with WOMAC_pain and WOMAC_total reduction after 6 months. Results: Fifty-four patients (22.2% male; median age, 69.4 years; median WOMAC_pain at baseline, 12) were evaluated. Of all OA features scored, a higher cartilage full-thickness defect score showed the strongest association with less reduction of both WOMAC_pain (B,−0.63 [95% confidence interval (CI), −0.91 to −0.34]; P <.001) and WOMAC_total scores (B, −1.77 [95% CI, −2.87 to −0.67]; P <.001) following treatment. The presence of grade 2–3 effusion synovitis (B, −2.99 [95% CI, −5.39 to −0.60]) bone marrow lesions (B, −0.52 [95% CI, −0.86 to −0.19]), osteophytes (B, −0.21 [95% CI, −0.36 to −0.06]), and cartilage defect surface area score (B, −0.25 [95% CI −0.42 to −0.08]) all showed a significant association with less WOMAC_pain reduction (all P <.05). Conclusions: In patients with mild-to-moderate symptomatic knee OA treated with GAE, the presence and severity of full-thickness cartilage defects, effusion synovitis, bone marrow lesions, osteophytes, and cartilage surface area scores at baseline are associated with less favorable clinical outcomes at 6 months.