My 11 year old rat terrier has never shown signs of a luxating patella until yesterday. I never heard a yelp or any sign that he had hurt himself, but his gait is a little off (not really sure what is different though because it's so slight), and when he sits, he doesn't bend and tuck his leg as far under his body, it's more off to the side and straighter. He's jumping and running as if nothing is bothering him. When he stands, he puts more of his weight on the other hip, and likes to keep the affected leg straight. I have also noticed that he has been liking to stretch more than usual. I know rat terriers are known for this problem so I assume that's what it is, but I was wondering if others of you have had similar experiences, or if you think a pulled muscle could be to blame? With a thorough exam and moving his leg all around/massaging it, nothing triggered a reaction, and he is usually very vocal with his pain. We will be taking him to a vet next week, but since he is acting like himself I'm not in a huge hurry. Just wanted to hear some experiences and advice from others until then. Thanks!