Dude, you can walk and be active in your daily life without an ACL. Hell, it was just released a while back that James Butler played several years in high school with no ACL in one knee. This can be done with proper muscle management that athletes tend to have. 4me is right, even a good athletic trainer can typically give you a pretty accurate assessment of the knee by doing various manipulations. They get the MRI to confirm but a knee injury of that magnitude is often accurately assessed before they've had the MRI. Now, I've never really heard of tests determining partial tears in a meniscus which is more of a shock absorption cartilage but the ACL is a different story.