Did Kiyoshi have an injured knee even before being seriously injured by Kirisaki Daīchi High?
After watching the episode, I think Kiyoshi started having the injury on his legs for playing too much. He may have known about it because he is tall, thus he will likely to injure his legs more than average size person (I read an article about tall basketball players are more prone to injury).

So yes, he was injured before his match against Kirisaki Daīchi High, and Makoto Hanamiya made it worse by injuring him.