Anyone who has handled many knee injuries can tell quite a bit by physically examining the knee and having the patient go through a range of movement.

Add to that a look at X-rays and MRIs...and sure they are going to have a good idea of what is going on.

There are plenty of massage therapists and physical therapists who can do the same thing.

As can an experienced sports trainer with a professional team.

It's not that doctors can't do it. It's that doctors won't take the time to do it.