When you analyze traumatic orthopedic injuries it is important to understand the physics. All that energy directed against biological tissue causes predictable havoc and destruction. Actually Tiger is very lucky to be alive. If the vector of all that kinetic energy were directed toward his head or neck, he would have been dead.
Before they fixed the chassis design, traumatic leg injuries were very common in Indianapolis racing crashes. The best guys to who developed the medical response to those are still around, Terry Trammel and Steve Olvey and Kevin Scheid.