I'm in your boat.
I have the ankle problem, cannot run ONE step since 2007. Try to play tennis with that slight incomberance. Singles can get really tough, which is why I say I can lose to the top of the heap 3.5 level singles guys.
I can swim OK, surf OK, windsurf with the best for an hour, even snowboard just fine for a couple of hours.
But beyond that narrow time frame, the game is over.
I try to play 3 doubles sets nowadays, no more, unless I don't have to windsurf in the afternoon.