GLUCOSAMINE

Adding Glucosamine would not be too much. Go with the glucosamine/chondroitin with MSM. There are several brands out there that should work fine. I really like these brands:

Synovi g3 chews
Connectin
Glyco-flex

Like I said, there are so many out there that some here may have had success with different ones, these are just what has worked really well for me.

A couple of years ago I had an old arthritic dog and I gave him the Kirkland (Costco) brand of glucosamine w/chondroitin.  It worked great for him - he was walking better at nearly 15 than he was at 13.  If I remember right, it was about $20 for a botte of 180 capsules and I rolled them in a little bit of peanut butter for him.

Joyce & Max

My 11 year old golden has been on MSM/Glucosamine for a couple years now.  He has a little arthritis in his hips and it was making him slow to get up and down, and also where he ALWAYS trotted except when on leash, he slowed it down.  But now he is back to that frisky trot all the time--sounds like a pony going thru the house.
 
My 6 1/2 year old golden had her right knee opertated on for luxating patella 5 years ago. and then just a little over a year later, had her other knee operated for the same thing, plus the Cru. lig.  I have her on just one of the MSM/Gluco caps a day, but she also gets a SynoviG3 chew, which I do get from my bet, but can be bought from Dr. Foster & Smith Catalog (I don't they they carry the chews, i could be wrong).  They, plus our 4 year old adopted golden mix get a fish oil, an EsterC, and a Foster & Smith  VitaCap for large dogs every day.
 
By the way, hubby and I take the same MSM/Gluco, EsterC and fish oil the dogs take. Get them at Walmart.