Non-Steroidal Anti-Inflammatory drug...like Rimadyl or Duramaxx. Like I said I don't really like them, but if I was nearing the point where mobility is becoming a serious issue, I would probably go with that. It's not something I would consider if the dog could possibly live a year or more in their current condition.
http://www.glucosamine-arthritis.org/arthritis-pets/NSAIDS-rimadyl-pets.html
http://www.glucosamine-arthritis.org/arthritis-pets/NSAIDS-rimadyl-pets.html