I have had excellent success with Traumeel on my own achy (human) knees as well as success using traumeel on a dog's achy shoulder (overworked digging holes).  Pain is tricky. I find it hard to know what works and doesn't based on observation alone except in the most extreme cases or brand-new pain.  the chronic pain various dogs i have had all hide pretty well, though they still suffer.  my experience has been that different kinds of pain require different medicine...particularly nerve pain (tingling, burning, throbbing due to nerve damage).  For example, my GSD has arthritis and a tail spinning / biting obsession.  Repeatedly biting her tail (we're now past the point where stitches are even an option: the last inch of her tail is l scar tissue) caused severe nerve pain and tramadol did not help one bit, even at large doses.  I'll admit I've tried animal communicators (aka pet psychics) to help sort this out, some of whom I think really do know how to read an animal, and others who are just taking my money.  One of these said "try gabapentin, this is what you want for nerve pain" and so I asked a qualified neurologist about this who was happy to prescribe it for Kendra having evaluated her.  The gabapentin does seem to work and helps reduce re-injury borne of fussing at open wounds.

I tried "Dog Gone Pain" -- this time for arthritis.  (Or was it bone cancer I didn't recognize yet???)  I did not see any results, but I did not finish the bottle, either.  It's so hard to know.  No ill effects, that I'm sure.

Between the two, I would definitely use Traumeel without hesitation, confident that it would soothe achy muscles and aid healing, plus it's 100% safe to try with no side effects or drug interactions.  i'm less confident about its ability to assist with chronic arthritis long-term except as a palliative. But for bruising and sore muscles it can't be beat.  A friend got in a motorcycle accident with nasty injuries, and claimed it worked better than any prescription drugs she was given.  It's expensive though...  i've been reassured by holistic vets that the traumeel lotion works through fur.  gently massage it in to the skin as much as you can.

the other thing i've tried, which has helped my arthritis and *may* be helping my dogs' arthritis (I have 3 dogs) is gelatin.  plain, unflavored, gelatin in the jello section of your supermarket.  half a packet per day per dog was what was recommended to me.  (if you decide to really go for it, buy it in bulk from amazon.)  i learned of this from 2 gals at Camp Unleashed, a summer camp for dogs and their people, who absolutely swore by it for their two dogs.  when i asked my primary care vet about it, she had not heard of it before, could not think of any contraindications and did not have any overt concerns, but said caution was warranted because she just did not know what the effects might be.  (She's very conservative.)  i certainly found no ill effects, and got only modest results, but also did not stay with it long...i think i ran out and forgot to replace it, then was travelling, etc. 

good luck to you!