Hello,
Yes a patella can sublux if one of the surrounding ligaments are not working. I'm having a medial patellar femoral ligament reconstruction because my patella keeps subluxing. The MPFl is not working so they are building me a new one . But, yes I would say go to another ortho. One doc is not going to admit their mistake, this gives grounds for a lawsuit, Please inform t he new surgeon, that you only want to fix the problem not go after the other doc, most orthos are very skeptical of operating on if another doc has already done so . Asa a matter of fact when you try to make the app, I would nto mention that until you actually see the doc .
Good luckto your mother, Give herr a hug for me ; I love elderly people.
Keep us posted
Tee