ACL doesn't heal by itself if clinically unstable. We can test the knee, do the same manoeuvre if the knee is moving like previously, suggest reconstruction surgery, because ligament don't heal itself even if you wait 5-10 years.
If you don't mind wearing knee guards, and can just stroll—you might not need surgery. However, patients must be compliant: if you forget to wear it will cause further damage. The problem is the ligament itself, once it stretches, on MRI we still can see one piece of tissue once it loses tension. If the knee is still moving or rocking, and some have a meniscus tear in the cartilage which means there’s damage, then I would advise surgery.
