Joint replacements are generally very successful, allowing most people who have them to return to active lives free of chronic pain. But while artificial joints are designed to last a long time, they won’t last forever. This means that if you’re a young, active person considering a hip or knee replacement, there’s a possibility that you’ll need to have the same joint replaced more than once. Just how long does a knee replacement last? And how many knee replacements can you have in a lifetime?