Is tramadol safer than rimadyl for long term pain management in my dog?

One of my dogs started having trouble getting up so I brought him to the vet. She recommended an xray and prescribed tramadol. I have another dog with grade 3 elbow dysplasia that I give rimadyl sometimes for the arthritis. My concern is that the rimadyl can damage her liver and kidneys with long term use and she needs regular blood work when she is taking it. I've had a holistic vet urge me to take her off it entirely and just do acupuncture. However she sometimes needs extra pain relief. Her arthritis is probably bad enough that she always has some pain. So I was wondering if tramadol might be a safer alternative to ask the vet about.