Older astroturf pitches are the reason that, at 34, i can sometimes stuggle to even walk without severe knee pain.
Granted that was from playing Hockey not football, and I was regularly twatted on my already dodgy knees with a wooden stick too, but still.
I can well understand LJ's point about some of the players. Those types of surfaces, albeit tjey're now of a better quality and standard than the 1980's and 1990's versions, are knee wreckers.
So, i would guess Kelly, Forte, Elekobi, Lockwood, B Wilson, Ibhere, and poss Turner would all be in danger if it ever happened...