Sid is missing a rear leg as you see in my avatar and is not a cancer dog (his hock 'exploded' when he broke it on the track, nothing to fix together).  He is three years post amp and we've had him a year. 

At first, he wasn't able to go very far, because he hadn't been taken for walks, but now he'll do a forty minute walk unless it's hot weather. If he were a different breed he'd probably be able to do more, but greyhounds are not endurance dogs.