Hi everyone,
From my experience I have learnt that if xrays show nothing and your vet is at a loss it might be because problems with nerves may not show up on xrays. I had similar problems with my border collie girls Zoey and Ziggy who are 8 and 10 and starting to slow up. The thought of an operation was terrible. I have since invested in a chiropractor in Brisbane who is great (pm me for details). He adjusted them and they walk perfectly now which I now realise they havent done for years. They were walking lame/limping as a result of having a pinched nerve and being in pain, no operation needed, we're all very happy! He these symptoms can result from a bad birth, mum stepping puppies, rough play, jumping/falling the wrong way, accidents, slipping on slippery floors or using stairs. I have had the best results I could ever have imagined and wish someone had told me earlier - so glad I didnt keep going to the vet and just medicating without treating the problem. Even with elbow displaysia and arthritis which the xrays showed there is now no sign of lameness so maybe this wasnt the cause at this point in time for my girls limping.... Good luck