This study investigates clinical outcome and imaging outcome parameters after intraarticular injection of steroids, platelet-rich-plasma (prp), hyaluronic acid or placebo in patients with early osteoarthritis of the knee joint.

Osteoarthritis of the knee joint is a very common disease in middle aged and elderly patients. This study evaluates the efficiency of different commonly used substances for intraarticular, non-operative treatment in early stages of this disease.

120 patients receive an fluoroscopic guided injection in the knee joint: 30 patients get injection with steroids 30 patients get injection with prp 30 patients get injection with hyaluronic acid 30 patients get injection with placebo (iopamiro contrast media)

Primary outcome: - clinical outcome (pain using numeric rating scale)

• Magnetic Resonance imaging (cartilage defects etc.)

Inclusion criteria:

• gonarthritis Kellgren 1,2,3 with symptoms
• german speaking
• informed consent

Exclusion criteria:

-age under 18, gonarthritis, Kellgren 4, anticoagulation therapy, known inflammatory disease or infection, cardiovascular disease NYHA IV, immunosuppression, contraindication for MRI, pregnancy, no informed consent, NSAR 3 days before injection, etc.