Knee operation
I walked around with a torn Menscus for a few months until the incompetent military quacks figured out through an orthoscopic surgery what was wrong and fixed the problem. If your exams are now and you cant go to a hospital, do the exams and then go for the surgery.
But if you have have time before your exams, say a week or so and you think you can sit through them with your leg being a bit sore the do it that way. Ask what your doc says anyways.
My ops was done a good 15 years ago and I have not had any real problems since. Pass the medical every year. (Fingers crossed that the trend continues)
The recovery itself was not too long. I was walking about in a day with sticks and in a week without. Running in 3 weeks and back in active duty in 4 weeks from the operation.