MMA experts Please Answer this!?

[JacainKnight]

This guys leg broke in a mma fight and i want you guy to explain what how did it break?

http://www.youtube.com/watch?NR=1&v=bAGPlr-Qvh4

and this one

http://www.youtube.com/watch?v=MH8t-okjT38

 

[Frankthetank1]

A previous injured cracked the bone, thus breaking with the final hit.