Marco van Bastens case is puzzling: why does a healthy, active teenager end up with a lasting disability from ankle osteoarthritis just a few years after a simple ankle sprain? To prevent this from happening again, we are developing a new tool that can measure right after the injury if there is damage in the ankle and how severe it is. In a large-scale study, we want to find out if this damage gets worse, leading to osteoarthritis. With this tool, and what we learn, we are hopefully able to treat osteoarthritis before it gets to a point-of-no-return.