Why has my dog gone lame?

I don't know if anyone out there can help shed any ideas regarding my Lurcher 'Rea'. She is a rescue, and we think she is now about 10 years old. I have had her for over four years and love her to bits but over the last few months, little things have been happening that have been causing concern.
We noticed her tail stopped wagging and was hanging slightly limp - she didn't appear to be in any pain, although she had earlier been running with our other rescue Saluki 'Dino' and the two of them had clashed and Rea had rolled over onto her tail and yelped. As she appeared to recover from this, we just carried on as usual.
A short while later - as in a month or so - one of her back legs has become lame. She isn't dragging it, but seems to be forcibly holding it off the ground. To get around she has been relying on her one working back leg which doesn't
look very comfortable at all. We took her to the vet as this didn't clear up after a day or so, and clearly was causing her discomfort. The vet prescribed anti-inflammatries and lead walks etc. She got on ok with these although after a bit, it needed the dose to be increased. Still, she was not really putting any pressure on the leg. We returned again to the vet, and this time X-rays were taken. It appeared to show a displaced hip which the vet feels she has possibly had since birth. She also felt the X-ray showed either arthritis or a tumour - she isn't sure which. She carried on with the treatment for arthritis.
We went back again for more tablets and she is going to conduct more X-rays. She feels that the length of time that Rea has been on the medication, she shouldn't really be as lame as she is on this leg, unless something 'bigger' is going on which she is not sure of. I feel it's just happened so suddenly and lasting for longer than I had anticipated, that I am not sure what it is. I am not sure whether the displaced hip is causing arthritis and would it be this severe that she really doesn't want to put pressure down etc. The vet is hinting that it may possibly be a tumour, but is not too sure until the other X-rays are done. Has anyone any other ideas? I really just want to ensure that Rea is as comfortable as possible and that we have covered all possiblities of what the issue may be. I would really appreciate it if everyone took some time to consider and respond.
Andrea


A common cause of hindleg lameness in older dogs is damaged or ruptured anterior cruciate ligament. This is located in the stifle joint. This might explain the sudden onset lameness. Perhaps your vet has already checked this but it might be worth another look.
John Burns BVMS MRCVS, Burns Pet Nutrition


I can understand how worrying this must be for you because we expect our dogs to run around and enjoy their exercise. A lame dog who does not improve on anti-inflammatories certainly needs further investigation so that a diagnosis can be made and appropriate treatment instigated, if possible.
You mention that your vet has found that Rea has a displaced hip. I imagine this is actually hip dysplasia because action would have been undertaken in an attempt to replace an acutely displaced or luxated hip. Hip dysplasia is a developmental problem where the hip joints are not the tightly fitting ball and socket joints one expects. It can become apparent at a young age, or be diagnosed at routine hip score assessment, or it may be picked up later in life on investigation of lameness when the effects of the body trying to stabilise the hip joints has resulted in arthritis. It may therefore be an incidental finding in Rea’s case, especially as she has not improved with anti-inflammatory painkillers.
I am intrigued by your description of Rea seeming to be forcibly holding a hindlimb off the ground. Is this the classic ‘tiptoe’ stance of a dog who has acutely ruptured a cruciate ligament? If so, then the problem lies within the stifle, and I wonder whether this is the joint your vet is planning to radiograph next?
Now, and this may be a red herring in your description, you do mention Rea’s tail hanging limply after the traumatic episode which seems to have started her problem. Although you say that she seemed to recover from this, so I assume you mean that she is now wagging her tail once more, I wonder whether she hurt her back when she was bowled over. The hindlimb lameness could therefore be sciatica, for example.
So, although one always worries about something sinister lurking, there are still possible orthopaedic explanations for Rea’s hindlimb lameness. Routine radiography may be sufficient to enable a diagnosis; otherwise, more involved procedures involving contrast media or different imaging methods may be necessary.
I do hope a diagnosis is reached which enables Rea to be treated and resume an active life once more.
Alison Logan, vet