I knelt down to get something in a low cupboard this evening and my knee exploded in a fiery ball of pain. It had been absolutely fine until I got past about 90 degrees. For the instant before it did whatever it did, I had the sensation of needing to crack my knee (not uncommon, I have very clicky knees). I'm resting, icing and elevating and so far there's no swelling. I can walk ok, slightly tentatively but not limping. I can't get close to a 90 degree bend though. The pain is behind my kneecap. I fully appreciate diagnosis by internet isn't a great idea but any ideas what it might be? I've never had a problem with my knee before. I'll call the physio if it's not improved by the weekend but I'd like to know what to avoid in the meantime.