Is your dog very symptomatic, Polar Bear?
I know that HD can be a devastating diagnosis, but it really isn't a death sentence. It
can be managed, even in older dogs like your girl.
We've had very good results with glucosamine/chondroitin supplements for joint problems.
Also, watch her weight--a little on the light side of normal is much easier on the joints than being overweight or even on the heavy side of normal.
Moderate exercise is good--and if you can find a low impact activity (like swimming, if she'll tolerate water), that would be very beneficial.
And anti-inflammatory drugs can be used when she overdoes it or seems particularly painful. There
is one that can be injected--but for the life of me, I can't remember the name.
Senility rears its ugly head again someone who remembers it will jump in soon. However, it's not a cure for HD, just a drug to mitigate some of the symptoms.
Best wishes for you and your girl, Polar Bear