Often the difficulty comes from a patient waiting too long to seek medical attention or they do not tell all their complaints to their treating doctor.   They can be concentrating only on one area of the body, eg: shoulder / back pain but forget about the ankle injury and thinks that it is only a sprain.  There are times when clinicians can get tunnel visioned in treating one area of significant injury but inadvertently do not address another area. Being trained in trauma surgery and reconstructive surgery, I have seen the neglected ankle sprain being a tendon rupture / ligament rupture, nerve damage, etc.     MRI’s and through physical exam by a specialist physician are very useful around the time of the injury to see active swelling, injury to the tissues in question.   This can help to answer the age old question of if this a new injury from this accident or a preexisting injury or even an aggravation of a preexisting condition.