When my Tizzie (Cockapoo, Rainbow Bridge) was up in years she too had arthritis. She had trouble getting up, couldn't tolerate a "sit" position, and occasionally her legs would give out lose the ability to hold her up, splaying out in different directions as she fell. It was so sad to see her so limited and having such difficulty. We tried the glucosamine and chrondrotin, aspirin, and the Rimadyl. Nothing seemed to make any difference. This was 3 years ago. Maybe there is something new on the market. The Drs. Foster and Smith catalog always seems to be advertising a number of products that portend to alleviate these type of symptoms.