Gus has been on the Rimadyl for a week now, and there has been no improvement. I have determined that his knee is what is causing him to limp. When the patella comes out of place and he does not walk on that leg, I can not only see that it is out of place, I can feel that it is. I am able to get it back in place simply by pulling his leg up into the position it is when he sits. With my other hand on his knee, I can feel it popping back into place. We will take him for the surgery to address the luxation. The orthopedic surgeon will not know until she is in there if he will require a TTA also. In all probability he will though because of how often the patella comes out of place. I cannot imagine there not being damage to the cranial cruciate ligament.