Just to add something slightly off the topic but may help someone out there. My rotti after xrays and limping on his front leg was found to have elbow displaysia. I tried cartrophen injections, sashas blend, fish oil tabs, glucosamine tabs, joint guard and techniflex but didnt see an improvement, too little too late. Specialist said he was not an option for elbow fusing or plates and instead put him in metacam, gabapentin/neurontin and tramal.
My vet suggested I try accupuncture or alternate therapy for pain relief. I ended up opting for chiropractic work and have learnt that although he has the structural/bone issues, and arthritis, he was limping because his shoulder was "out" and he had a pinched nerve causing him to eventually limp when the pain got too much and xrays dont show nerves apparently.
My boy was weaned off his medication about 5 months ago and now is on nothing and has no limp at all but has adjustments when required if he has a "silly" episode and runs around and hurts himself. AMAZING and very happy he'll see his 8th birthday now as he was at the stage that I was taking his food and water bowl to him!
They are such pain tolerant creatures, good luck to all those limping now - wise decisions and fast recoveries to you all.