I'm satisfied with a merciful end to Marc Bulger's career with the St. Louis Rams, but if you just can't get enough info about his cracked tibia, here's just what you're looking for.
Technically, it's a tibia plateau fracture. If you're looking for a comparable injury situation, there aren't many to be had. Joe Paterno suffered the same thing when his leg got steamrolled as a play bled into the sidelines. As for NFL players dealing with the same thing and what it might mean for Marc Bulger's future:
Besides that, the only records we have of NFL players suffering the injury are linemen. Such a fracture ended Bengals lineman Rich Braham's career in 2005, while late Oilers defensive lineman Jeff Alm had the same injury shortly before committing suicide during the 1993 season.
It sounds like a good bet that Bulger's season has ended. I suspect we might still see a move to IR in the near future too. Career ending? We'll have to wait and see.