What hip surgery? You think he would be sitting on the bed like that if he had got a fractured hip, huh? With how lively he is, he has absolutely nothing going on but something toward his foot. He did say leg, the cast is where it is, so it ought to be either fibula or tibia. Although that being said, it could be foot bones and he just wasn't so precise with his words.
Sorry, but I won't take your word for Japan keeping people utterly unnecessarily lying in hospitals. Who would even want to be there if they have got a decent home waiting for them? With Juri around, Kouki doesn't even need Japan's famous night shift nurses, haha.