I heard originally, although I can't find it now, that the repair in 2005 used graft tissue from elsewhere in Carson's body, which isn't as strong as the donor ligaments that are more commonly used today.
I didn't stay at a Holiday Inn Express last night, but my wife is an athletic trainer and works in an ortho clinic. One of her old docs was a 20th overall pick in the 1st round and played 5 years in the NFL.