Sid started with limping last February, right about the time he had a seizure that we finally discovered was being caused by gallstones. It was his left front leg/shoulder and they figured it was arthritis. Took Rimadyl for few days, started some glucosamine and he was fine until a few weeks ago - when the weather started to change here. Now, he was really limping on left side, seemed to be putting a lot of weight on his right left which seems somewhat stiff and a little limpy now too. He also didn't want to bare weight on it last night and we lifted him in and out of bed. Usually a day or two on the Rimadyl at the first signs of limping helps him, but not this time. He has been on it since Saturday and that is why my husband and I took him to the vet this a.m. He is also a pretty big boxer. He weighed in at 87.7lbs this morning, but he is built and gets lots of exercise with my son, who is 11. He is such a beautiful creature - reverse brindle with two cute little white toes on each foot!! Sorry so long - just trying to give plenty of background because I am worried and none of us would know what to do without him in our lives. We didn't think we would have to do this until he was older, but that is okay. He is still a blessing!
By the way, THANKS SO MUCH to everyone who has responded so far. I really appreciate the kind words and the info.!!