The care they get is amazing too. My mate did his leg playing football in the place as Shearer. Big Al was up playing again in 9 months or whatever it was, my mate was told not to do anything like play football, go skiing etc ever again. Not sure what the difference is though, repaired is repaired surely.
At Stevenage we had signed a forward from Gateshead called Paul Thompson, he looked outstanding in his first few pre-season games then broke his ankle in the next. Will never forget him sitting pointing at his foot which was turned at a horrible angle.
He came back, but never quite seemed the same again and ended up dropping back down the pyramid to play for Gateshead again. Of course he might not have made it without the injury, but he had shown enough in the games before the injury to appear to have a chance.
Apparently his ankle damage was very similar to Shearer's, so I guess there's an element of fortune in the extent to which your recovery enables you to come back. There may even be some psychological effect - if it's on your mind, or you aren't confident that it's right, then you aren't going to be able to commit 100% when you need to.
And of course the amount of personal care you can get with the physio will have a massive impact on how much strength and confidence you get back. The likes of Shearer and Eduardo had and will have a better chance of a full recovery than those playing at much lower levels.