We can help you understand some of the language used to describe your condition. To gain a better grasp of the actual pathology, it may be best to contact the radiologist directly. If you are under the care of an orthopedic surgeon, she or he can go over the MRIs and results with you as well.
As you probably already know, ACL refers to the anterior cruciate ligament. It's one of two key ligaments inside the knee. ACL deficiency suggests the ACL is torn or injured and unable to perform its function.
Concomitant means "at the same time." So along with the ACL tear, there are some other problems. Intra-articular means the trouble lies inside the joint. This could be the meniscus, bone, or capsule. Extra-articular would mean outside the joint.