Whether an ACL injury has healed or not is determined by the physician based on clinical signs and imaging tests. An ACL injury usually presents with symptoms such as knee pain, swelling, limited movement, or joint instability such as unsteady walking and joint wobbling. If the clinical symptoms disappear, the results of drawer test, Lachman test and axial shift test are negative, and there is no abnormality in arthroscopy and MRI, then it can be judged that the ACL injury has been healed. Most of the patients can regain normal knee function if the ACL injury is treated early and rehabilitation training is carried out gradually. It is recommended to follow the doctor’s advice for regular review, and go to the hospital if the joint swelling and pain worsen during the rehabilitation process.