Hi, there! If I say Mike broke his knee, I think I mean Mike broke or fractured his bone in his knee rather than just broke the skin on the knee. Am I right? When doing translation today, I saw someone had translated the latter situation (break the skin on the knee) as "break your knee", which I think totally different. Needless to say, "break your knee" is much more severe. And how will you describe this kind of injury? And is "break the skin on his knee" acceptable? Would you please share your answer with me?