Saw the knee specialist this afternoon...he did more xrays and a more in-depth look at the MRI. The ACL is detached, we knew that, but rather than a lateral ligament tear, the medial meniscus (on the inside of the knee) is torn, and both the large bones are bruised badly -- it shows up on the xray as big white patches. He said it may take a year for the bruising to heal.
I'm off the crutches and walking with a cane. I'm going to do two months of physical therapy, to see if the knee will stabilise, then I will see the doc again and we will talk if surgery is needed.
.....and the cold has become flu, and I've lost my voice. =-P