Wigs,
What you wrote below isn't 100% accurate, though it's probably what your recruiter told you. The bottom line is NAMI (Navy Aerospace Medicine Institute) wants to make sure the retained hardware isn't covering up an underlying condition, i.e., would you be OK without it. Do a search and go to the NAMI website (or try the link I put in below). You will find a link to the Aeromedical Reference and Waiver Guide. Click this link and look for the section about orthopedics. The first topic when you click this link is retained hardware. You will notice it says NCD assuming a few criteria are met. NCD = Not Considered Disqualifying. As long as you have no pain or limited mobility, and the problem which required the plate is resolved, you'll be fine. A word to the wise, start asking the surgeon who put it in for any documentation he has. My surgeon happened to be a former Army Doc so he wrote me a letter stating I had full range of motion, etc. As the NAMI website says, you may not even need a waiver. Read up and good luck.
LTJG Garrison
http://www.nomi.med.navy.mil/Text/NAMI/WaiverGuideTopics/orthopedics.htm