US Navy checking medical history?

I have recently enlisted into the US navy. My recruiter told me that unlike other branches where the enlistment standards are lowered and they are just looking for a few trigger-pullers(except the air force), the navy is looking for high quality candidates. He told me that they are looking for any reason to send you home and not let you enlist so anything like broken bones or major surgery could disqualify you. I have only had acl surgery but my recruiter told me they would not let me enlist with that so he took it off my papers and told me to lie and to act as if it never happened. He said the navy can't and doesn't really look at your medical history unless they have some real reason to look it up. He told me "No" gets you in the navy and "Yes" gets you sent home. So I did everything he said and my process went smooth and I enlisted and am waiting to ship out. My only question is can and will the navy ever look at my medical history and if they do find out about the surgery, will they discharge me? I have no other problems and no criminal background or record and my knee is fine and functions like normal.