Originally Posted by
stapfam
With medical science so good nowadays- Almost any Injury can be overcome. Saul Raisin had to give up racing after brain damage in a crash. He got through it-got himself fit enough to get back racing- only to be told that any further accidents that involved a head injury- Might kill him or turn him into a cabbage for the rest of his life. No team is prepared to take the chance of that injury occuring so he has had to retire. He still rides but no longer competitively.
I specified the Kidney, lung and head thing because in fact if you do lose one lung or kidney most doctors will advise you to take it easy as you only have one left and once it is gone, life really sucks or is not there at all. As to Saul he strikes me as the perfect case for the question of the OP as he did in fact have to retire due to his injury whether voluntary on his part or the liability fears of his teams.
Items medical science often cannot fix-
Brains
Spinal Chord
immune system
livers
lungs
kidneys
Hearts
(basically anything where a transplant is required is something they can't fix, they can replace but cannot fix, and event he replacement often leaves you at a lower level for the rest of your life)
Just ask any doctor coming back from Iraq about all the things medical science cannot fix. They do a lot, but we are still a long ways away from the "I can do anything to my body and expect a full recovery" era.