Didn't know about his injury, and this is no insult to his injury but I was found the fight scenes quite stiff, it wasn't THAT bad but it could've been better with more experienced martial artist actors.
I think in the special features for the first movie Keanu even admits this a little bit because he couldn't really move his neck/head much for the fight scenes because of the injury. It's also why Keanu doesn't throw many kicks in the first movie either.
FWIW I think the fights in the sequels are a lot more fluid