When doctors diagnose a torn ligament, it’s usually because they can see ruptures in the ligament’s collagen fibers, visible on a variety of different scans. However, they also often treat patients with many of the symptoms of a tear, but whose ligaments don’t show this kind of damage. Researchers from the University of Pennsylvania are using network science to gain new insights into these “sub failure” injuries, which can lead to pain and dysfunction despite the lack of obvious physical evidence. The mechanisms that lead to these symptoms happen on a microscopic level and can’t be detected by existing clinical tools.