Answer:
No
Step-by-step explanation:
A concussion is simply a type of brain injury in which some form of trauma causes the brain to clash with the wall(s) of the skull, causing a temporary alteration in the brain's normal functioning. Though the symptoms of such an injury can include a loss of consciousness (which we know as a "knockout"), it is not a requirement in the diagnosis of a concussion. In fact, less than 10% of the sports-related concussions in children involved a knockout event and more than 90% of all concussions do not result in a loss of consciousness.
So to answer this question, no, having a concussion does not always knock you out.
However, the inverse may be true; if you experienced a knockout event following a trauma in which your brain made violent contact with the inside of the skull, chances are a concussion has occurred and further workup to assess for internal bleeding and structural damage should be sought.