It could be the repair that is causing the problem- that it didn't heal or he could have some arthritic changes causing the swelling. What did his dr. say about it?
his first surgery was a repair but today he took some anti-inflamatory medicine and he said within a half hour he was noticing a difference (he never really took any before). Is it almost a definate that he will need to have the second surgery or could the swelling just be from getting back to running? when they took the fluid out the other day, it stayed unswollen until he ran 4 miles.
When he had his first surgery, did he have the meniscus repaired or was the tear just debrided (cleaned up)? If he had a repair, it could be that it didn't heal and if that's the case, he would need another scope to go in, remove the prior repair and, most likely, debride the tear instead of repair it again. It all depends on what the first surgery entailed and what they find should they go back in again.