I had an arthroscopic procedure on my knee for a torn meniscus. I kept from flying for a couple of weeks and then resumed normal activities once I completed physical therapy.
The following spring, I went for a 3rd class medical. I saw an AME I hadn't previously been to. It turns out he's an occupational medicine guy who doesn't do very many FAA medicals. He took one look at the medical history declaration and said he was "required" to defer my medical. Took me nearly a year, a lot of research, and then a lot of effort to convince the ortho surgeon and my primary care doctors exactly what I needed from them to get my medical back. I ended up typing the letters myself and having the doctors read and approve them, then have their office managers print them out on their letterhead, have them sign them and rubber stamp them, then mail all that plus the supporting documents to the FAA, then wait 3 months.
2 years later, I told this story to the AME I now go to. He said the whole thing was needless BS. That my procedure did not automatically require deferral as the previous guy had said.