Is there something more I can do to help my client with this (painful right knee) and is there more you can do?

We cannot take away the choices within her to agonize over the past. This is a normal human property and trait. However, we will do some work to temper things a bit and this can be reinforced at your end by giving her encouragement that we have done further healing and that this will be on the mend over some period of time, and the best approach would be to let this go and not agonize over it, with the expectation that it will resolve.