Understanding ACL Tear Symptoms And the Need for Surgery A knee injury can happen unexpectedly during sports, exercise, or everyday activities. You hear a "pop." Your knee swells and feels weak. It is easy to overlook these symptoms and expect the knee to recover naturally. But these could be https://medium.com/@linda.wockhardthospitals/acl-tear-symptoms-when-do-you-need-surgery-f78944034324