My uncle is a private consultant for media and newspaper firms who are trying to streamline and adapt to the new age of media, but he at one time was a lowly sports photographer for a medium sized southern city's newspaper. He was covering an NFL game and was shooting a picture when he was hit from the side by a 250 lb NFL player, hyper extending his knee sideways. It was very gruesome and disgusting, and he was in a cast and needed crutches for quite some time. He couldn't drive a car for at least two months and his wife had to drive him around. That shouldn't be a problem for Kane though, I'm sure he can afford a cab.
Years ago a Ravens receiver Qadry Ismail was running back a kickoff and got hit and his knee bent backwards. He was helped off the field and everyone figured he was done. Amazingly he was stretching and jogging on the sideline minutes later. He was injured and missed the rest of the game, but while things were stretched or sprained, no serious damage was done. So you never know.
Having said that I wouldn't be amazed if Kane was gone for a while.