The 12 Rounds star thought he would be going under the knife for a routine operation, but doctors discovered he needed a whole new joint in his right arm after years of wear and tear from his days in the ring.
During an appearance on U.S. talk show Live! With Kelly and Michael, Cena says, ""It's OK... I thought it was gonna be a basic scope but then they found that my elbow was old and worn so they drilled a lot more holes in it.
""I got a new elbow, but I can't quite move it yet.""
But Cena doesn't expect to be out of action for long: ""Pretty soon I'll be back and beating people up!""