If you have a body part held together with a boatload of metal and you plunge that body part into ice water, the area gets very cold very fast and stays that way for quite some time. Crikey!
I guess it depends on what type of metal and how close the metal is to the, uh, surface… I’ve never had that feeling with my titanium-plated wrist. 
Ditto with my titanium-infused femur bone in my leg.
Jumping into a frozen lake with brass balls isn’t a problem; in fact, they’re a necessity.
One of my friends is an autobody repair guy. He had heart surgery and has staples or something holding him together. A couple of weeks ago, he was holding a curved electric welder close to his chest. The magnitally charged tool slammed into his chest and knocked him over.
“Turns out, the Doc had a whole bunch of bits of metal we didn’t know about in him and when they turned on the MRI, he went all ‘jiffy-pop’ on us.” --Sgt. Hatred.
I *hate *it when that happens!!