My three year old Boston had a luxating patella. She had successful surgery in March and made a full recovery. She started limping again on the same leg a month ago. I took her to the surgeon and they did x-rays, and found nothing wrong. She started to improve with her pain killers, but has recently regressed. She is very hyper and likes to run...Sometimes I can't prevent it. I'm starting to think it could be her hip. Any suggestions? How can a little dog have so many problems?