Serious question - help with osteoarthritis in lab?

Its a long story but basically Ive taken on a 5 yr old lab x golden who was obese and stuffed with biscuits and cakes!!. Over 4 months Ive worked with him and got his weight down from 94lb to 85lb and its ongoing. He has had intermittent lameness over the last few wks and has been diagnosed today with mild OA. I'm now overhaulin his diet to get the rest of the weight off but obviously can't run him when he is lame. My question is for those dog owners who have experienced this condition. I would love some advice on how u deal with it? Im considering Glucosamine supplements but is there anything esle I can do? He is on Royal Canin Obesity management at mo. Would a raw meat diet help instead? Any help would be greatly appreciated. Thanks