How can you tell if your ligaments healed after dislocating your kneecap without an mri?

Less pain. Hello there, if your pain has subsided and you have little to no discomfort moving your knee cap towards the side where you disclocated it there is a good chance the ligaments have healed. However, healed ligaments in this setting are not "good as new" which means there is a chance for dislocating the knee cap again. That is where good physical therapy and strengthening comes into play.
No pain with movemen. If active knee extension does not yield pain.