When doctors examined an X-ray image of the knees of a woman experiencing severe joint pain, they found a gold mine: hundreds of tiny gold acupuncture needles left in her tissue.The 65-year-old South Korean woman had previously been diagnosed with osteoarthritis, a condition in which the cartilage and bones within the joints degrade, causing pain and stiffness.But when pain relievers and anti-inflammatory drugs didn't alleviate the pain in her knees and only caused stomach discomfort, she had turned to acupuncture, she told her doctors. The needles, which were presumably made of gold, were intentionally left in her tissue for continued stimulation, her doctors wrote in the New England Journal of Medicine in December 2013.