Plate Rich Plasma (PRP) is a new treatment for tendinopathy. A high concentration of blood platelets is made from the patients own blod, and then injected into the tendon. The idea is that the complex mixture of growth factors within the platelets can stimulate the healing process of the tendon. We want to address the efficacy and safety of this new treatment and compare it to either the best documented treatment, Steroid injection, or to a saline solution. We want to make a randomized controlled trial with 60 participants, 20 in each of the 3 groups, and a 12 months follow up. All injections are guided by ultrasonography.