You're right, but the confusion is, was it before or after Hurley knew about the surgery. In my opinion, it I put my detective hat on and put all the pieces of the puzzle together, DH suggested that he would miss some time but that it wouldn't be much, then he told us about the specialist, and then we found out about the surgery. I don't see any way that the specialist looks at Bouk's elbow and says, " We need surgery right now!" UNLESS it's an extremely minor procedure. It's not like this was an emergency surgery where he was rushed to the hospital for a major surgery.
So, to recap, my conclusion is that Hurley definitely knew about the surgery and that it was planned going into the specialist visit, OR the specialist determined that after looking at the MRI results that day, that it would be best if he went in quick and cleaned it up, which would constitute a minor surgery.
So, 2-4 weeks checks out. Just my opinion putting all the pieces together that we know of.