Yes, endurance running can certainly do this. Look at Olympic marathon runners. They look like unhealthy, spooky skeletons. If you have lead poisoning, you should begin taking high dose vitamin C until substantial amounts of lead leave your body. Your best bet to quickly stabilize the health of your knee and alleviate the pain is to apply steroids such as pregnenolone, progesterone, or testosterone or T3—the active thyroid hormone—to the area. Pregnenolone is probably what you want as it has the potential to convert to alternative hormones if your body needs something else. Progesterone converts as well, and if pregnenolone is hard to find, progesterone is more likely available (probably cheaper too). Transdermal magnesium may also provide great relief.
During lead poisoning, vitamin C levels may drop, and so will vitamin E levels as vitamin C recycles vitamin E. There would be a general trend for increased oxidative stress, and this may be a factor in your current state of pain. Consider applying vitamin E directly on the knee and supplementing selenomethionine to increase glutathione production.
Long term the only cure is to stop endurance running. After health is recovered, running may become possible again, but only short distance sprints should be recommended.