My boy has luxating patella but I have never heard him yelp or anything with it. Ask your vet to show you how to massage the area and push on the knee. My vet showed me how to do it. Sammy also takes glucosamine chondroiton (Spelling?). He did not like the chewable ones from the vet so my vet said he can take people glucosamine. I got the large tablets and cut them into 4's. He takes it with peanut butter and he is doing so much better. Hope your doggie is better!!!