PFS 10

As Aviation Ordnanceman in the Navy, you're always lifting and loading weapons, so you use your legs quite often. I've had knee problems before, but the pain was always something I could handle through physical therapy. A few weeks ago, though, and I felt a stabbing pain at the top of my knee. I didn't think anything of it, but it didn't go away. A couple of days later I was sitting down at work, and when I stood up it felt like my knee was going to give away. I couldn't figure out what I'd done that could have caused this. Normally, I did my own PT and could deal with it, but this was a new kind of pain. I went to the Naval Hospital, where a nurse practicioner said he thought it was PFS. It's hurting when I put pressure on my leg, when I run, if it just happens to twist the wrong way, I had just never heard of PFS and I didn't know what it was. The nurse didn't really explain it, so if someone could help, I would be great appreciative. I'd really rather it not get worse than what it is, because I love my job, and if you're an AO, you know what I mean. Please help!!!