iOrtho+ Free This is a very good intro to the paid version of Iortho. In this version you can articulate the knee and the ankle. There are fracture tests, ligament tests, tendon tests, etc. All of the tests come with directions and a picture. I do wish the navigation for this app was a bit better. I found it hard to find my way around and I'm still not sure what the big RED X's on the pictures signify.