Broke mine the first day of summer 1992. It was only a hairline fracture that occurred when a steering wheel forced a posterior dislocation. The neck side end of my left collar bone got pushed behind some other stuff- very painful. They put me out and put a clamp on the bone and maneuvered it back into position. Needless to say the break was slight compared to the other damage. Six weeks in a figure 8 brace and a lot of not doing anything made it better and there are no continuing effects..