In this double blind randomized sham controlled study the investigators want to establish the efficacy of transcatheter arterial embolization of neovessels for patients with symptomatic mild to moderate knee osteoarthritis after 4 months compared to a sham-embolization.

Rationale:

Transcatheter arterial embolization has recently been proposed as an efficacious therapy for therapy-resistant osteoarthritis of the knee, providing substantial pain reduction at short-term as well as long-term follow-up up till 4 years.

A potential working mechanism of treatment effect is that the normalization of the amount of blood vessels and blood flow achieved by embolization reduces inflammation, resulting in pain reduction

Objective:

The main objective is to assess whether transcatheter arterial embolization of neovessels in patients with symptomatic knee OA results in significant pain reduction after 4 months compared to sham treatment.

The investigators hypothesize that novel transcatheter arterial embolization of neovessels is a feasible, effective, and safe treatment for patients with symptomatic radiographic knee OA, resulting in significant improvement of pain symptoms in a period of 4 months follow-up compared to sham embolization.

Secondary objectives are

1. to assess whether reduction of neovessels is related to pain relief,
2. to explore whether decrease of inflammation is a mediating factor between neovessel reduction and pain relief,
3. to assess whether transcatheter arterial embolization reduction of neovessels decreases peripheral and central pain sensitization and
4. to assess whether transcatheter arterial embolization improve the outcome at 1, 4, 8 and 12 months compared to placebo of the: ICOAP, painDETECT, EQ-5D-5L questionnaires and NRS for pain.

Inclusion Criteria:

• Age.≥18 years
• Knee pain for a duration of ≥ 6 months
• Knee pain (numeric rating scale ≥4 - ≤8) on at least half of the days in the preceding month at time of inclusion.
• There is insufficient response of conservative treatment for at least 6 months
• Radiographic knee osteoarthritis (radiographic Kellgren and Lawrence grade 1-3)

Exlusion criteria:

• Contra-indications for MRI (e.g. metallic foreign bodies, etc.)
• Contra-indications for angiography
• Renal insufficiency, checked with blood sample test (GFR < 30 ml/min/1, 73 m2);
• Known allergy to contrast agents;
• Patient has known allergies to barium sulfate, 3-aminopropyltrialkoxysilane, polyphosphazene
• Women who are pregnant or lactating
• Intermittent claudication of affected limb
• Intra articular injections in the ipsilateral knee less than 6 months ago
• On the waiting list for joint replacement surgery
• Amitriptyline usage.
• Patient has known allergies to barium sulfate, 3-aminopropyltrialkoxysilane, polyphosphazene.
• Insufficient command of the Dutch or English language.
• Legally incompetent adults.

We are willing the share all our available unidentified data on reasonable request

is available upon request as of now and will be available for the next 15 years.

• after written request to PI
• after signing Data Transfer Agreement
• No commercial use for data allowed by requesting party.

Double blinded