Iloprost therapy achieves good clinical and radiological short and mid-term outcomes in patients with idiopathic aseptic osteonecrosis of the knee joint also in ARCO level II.

AIMS: The aim of this retrospective study was the evaluation of the patient-reported and radiological outcome of intravenous Iloprost therapy in the treatment of spontaneous osteonecrosis of the knee (SONK). METHODS: 36 patients (age 57.3 ± 8.7 years, 38.9% women, 61.1% men) who received Iloprost between 2018 and 2021 due to SONK (ARCO I and II) were included in this retrospective cohort study. Outcome was evaluated by pre- and postinterventional pain (Numeric Rating Scale - NRS), patient reported outcome (subjective knee value (SKV), Oxford Knee Score (OKS)) at latest follow-up (2.9 months ± 1) as well as quantitative artificial intelligence assisted analysis of bone marrow edema (BME) in Magnetic Resonance Imaging (MRI) before and after 3 months. RESULTS: Radiologically, there was a 71% reduction in edema (pre-intervention: 37.0 cm³±37.7, post-intervention: 10.8 cm³ ± 14.9, p < 0.01). Overall satisfaction was 2.0 ± 1.3, SKV was 83.3%±16.6 and NRS at follow-up was 1.3 ± 1.8. OKS reached 33.6 ± 12.0. No major complications were observed. Rare side effects were dizziness which required premature termination of Ilomedin therapy on day 3. CONCLUSION: Iloprost treatment seems a safe and promising therapeutic option also in SONK with excellent subjective outcome and reduction of BME of 70% within 3 months after Iloprost infusion.