Thank you one and all for your words of encouragement.  As I mentioned in a response to another poster, I wish I'd found this site back in September of 2011.  My wife and I sort of "flew blind" and the information here is fantastic.

A little more about Gus...

Prior to surgery, he was around 115 and was lean by Berner standards.  Now, he's around 90 lbs without an ounce of fat on him.  He's had a litany of orthopedic issues including elbow displasia, OCD, and cervical stenosis so we've always kept a close eye on his weight.  Yes, we got ourselves a lemon!  Anyway, as he will be 9 in just a few days, he's already exceeded the life expectancy for the breed.  That isn't to say we wouldn't love to have him for another few years, but we don't get too far ahead of ourselves and look towards monthly milestones.  Honestly, as devastated as we'll be, the last 18 months have been a gift considering the grim prognosis with or without the amputation.  HS is a sinister disease and all too common for Bernese Mountain Dogs. 

After we took him off Previcox (anti-inflammatory), we noticed an immediate difference.  He struggles a bit getting up, particularly after he's been laying down for an extended period of time.  He can do it, but you can see that his hind leg is bothering him a bit.  He's also refusing to go up stairs and will instead bark until someone comes outside to help him up to our back deck whereas before he'd climb them without assistance.  Once he's up, his leg appears to grow stronger, but our walks have grown shorter with more frequent rest breaks.  I usually walk him once a day for about 10 minutes whereas before it was closer to 20.  It was never a "brisk" walk though.  I let him dictate the pace and keep close watch for signs that he's tired.  We used to take him to the dog park once a week, but we've scaled that back because it would wipe him out.

His regular vet thinks it's just age and arthritis and I concur.  The tricky part is finding him some relief but not at the expense of his liver and kidneys.  Right now, we're giving him Gabapentin for pain, although he doesn't whimper or howl and it doesn't seem to help all that much.  Like I said, there was a pronounced change after discontinuing the Previcox.  Now I'm trying to find something else that has anti-inflammatory properties that's easier on his liver/kidneys.     

You are very conscientious and doing everything right for Gus. I too would have to agree that it sounds like age and arthritis and life on three legs taking its toll, so I would highly recommend checking out the Adequan shots. They aren't cheap but they've made a profound difference in many dogs' lives. Let us know what your vet says about their interaction with liver/kidneys, I'm curious to know about that. Gus sounds like a real sweetie. Give him a big hug from us and post some pics when you have time.

Just spoke to the vet.  Apparently, Adequan doesn't cause any undue stress to the liver and kidneys.  We're going to begin a treatment next week.  I'll keep the board posted (in the correct forum) on how it goes. Thanks