The doctor said i have an "avulsion-fracture." what is that?

Avulsion fractures: Avulsion fractures occur when you experience a traumatic injury involving a tendon or ligament interface with bone. When this occurs, either the bone or the ligament is going to fail. In an avulsion fracture, the bone fails to resist the traumatic force subsequently fracturing and still attached to the ligament pulling on it. They are very common, especially in younger individuals.