Complete speculation on my part but given the many knee injuries I've had....with a joint or bruised knee injury often times they try a long term lubricant like a synvsc injection into the knee. It does work really well and in particular will last 6 or so months, unlike others on the market. However it isn't like a cortisone deal where you just inject it. Something like synvsc requires specific placement, so an ultra sound is almost always required during the procedure, it isn't a big deal just a long ass needle and they move it around while watching the ultra sound. I'm completely guessing but since he had to visit the hospital it seems more likely this is the case in some form.
