4 million Americans now implanted with artificial knees

About 1 in 20 Americans now have artificial knee replacements, according to a recent study by researchers at Harvard’s Brigham and Women’s Hospital. That means about 4 million people have undergone the joint replacement operation, which costs about $40,000. Authorities said the data was important because many of these patients will require follow-up procedures and care as these artificial joints wear out in coming decades.