Originally Posted by milost
Yeah, but you're not a billionaire that has a CEO inventor that can give you "just the thing" for your knee injury.
Bruce Wayne does. It's ludicrous that he wouldn't have one or wasn't given one during those 8 years. Not to be able bodied for Batman (though that would be nice if Gotham wasn't miraculously cleaned of "serious crime"), but for Bruce Wayne. Staying in the mansion for 8 years, doing absolutely nothing? I know he was frozen in time but he wouldn't even try to walk right without a cane?
The injury and knee brace was simply a forced plot device that's simply done away with after the first half or so of the movie. There is no logic behind it. Wayne suffered from more serious injuries in the past and already had the technology to deal with it.
It serves more as symbolic of Batman (since Bruce gets the leg brace just to be Batman for a bit) being a quick fix bandage for him. Notice how the leg brace disappears when he starts to learn his lesson in The Pit about learning to live as Bruce Wayne.