I am surprised that she is not using it if it is a stage 2. I would definitely want them to repair that. That is the rule of thumb that the orthopedic surgeon I use tells me to use: contact them if there is a problem with ambulation.
To my knowledge, walking them is fine. It is the running and jumping that is a concern.
Do you have stairs and/or ramps to your furniture? A friend of mine has this ramp that she swears by....I am planning on buying one:
http://www.pawsteps.com/