After an MRI, a couple of doctor's visits, and a physical therapy session (and at least one hefty medical bill), it looks like nothing is going to happen with my knee, at least for a couple of months. Since most of the discomfort is gone at this point, and all that remains is the "locking" of the knee (which I've learned to work around at this point), the doctor's recommendation is to let it be for now, and see if the loose body that's floating around in the back of my knee either re-asorbs, or settles in somewhere. If I'm still having issues in a few months, they'll probably choose to scope it.