Poor Rourke! I am trying to remember when Casper was diagnosed? Hmmm... I think he was around 6 years old. He had arthritis in both hips due to HD ( one hip mild and one moderate) and Ankolysing spondylitis in his back, causing bony osteocytes, stiffness due to bone modification. It was demoralising at the time, as well as a bit of a shock. I mean jeez... to have arthritis in both hips and back...

The initial treatment was a month of NSAIDs and Yumove Advance. Front-loading the dose of Yumove for a month, then down to a maintenance dose. We also had to reduce exercise for I think it was around a couple of weeks, just to let things calm down. Casper is very stoic in nature, so dialling back the exercise for a bit, was important to ease the acute symptoms.
The improvement at 6 weeks was so good, Casper came of the daily NSAIDs, and we were to continue the Yumove Advance. Roll forward a few years and he getting a little stiffer. We are now seeing the most amazing rehab vet once a month, where Casper has acupuncture, cold laser and hydrotherapy. We also have very specific exercises to address any muscle imbalance and strengthen his core. Dogs with a bit of pain can favour one leg, for example, which can affect gait, and has a knock on effect on other muscle groups.
Earlier this year we had Benson in the wars, he already has arthritis in both front wrists and both elbows, so we have exercise/diet regimes in place for both of them.
Anyhow, going back to Casper, he is knocking on 10 years old. We really didn't he would be anywhere as mobile as he is now. I do think there is more out there to support dogs with arthritis, certainly to help slow down progression and maintain a good quality of life.
This link came up on BRX, it might have some useful stuff on it...
Canine Arthritis Management