Robin ~

You might try making a sling to help Katie move around...

Take a Bath Towel - and either *fold* or *roll* it along the LONG dimension -
to make a Long, narrow strip ~

Then slip it under her hind quarters (side to side) -
just in front of her rear legs.

Encourage her to *stand* - then pick UP on each end of the towel roll -
you'll be able to take almost ALL of her weight off her rear legs.

Be sure to *PRACTICE* inside - but if she catches on -
you should be able to *help* her up and down steps.

*TRICK* is you have to keep her "lined up & square" -
so she can *balance* squarely with her front legs.

{{{HUGS}}} & Prayers to you both