Just read this at Rafa's site, VB. I don't know the details, this is all I've heard and I don't think it's been mentioned here. Posted by sirene on VB:
"about last night taping of Andy's knee: Andy has a special right knee: as far as I understood he was born with a kneecap in two parts and that has caused him quite a few problems already. I understand that he can"t do anything against it, and that it won't prevent him from playing but at times when something happens somewhere else on his leg - like slight tweaking of ankle - the kneecap bothers him. Too bad for him, but like Rafa, he has to learn to live with it."