Biscuit's Bad Leg

Holly has this question about her dog...

I've taken my 10-year-old mixed breed, Biscuit, in to be seeing by the vet on a regular (well pet) schedule.  She is 10 years old, a border collie/ shepherd/??? mix.  She had issues with diarrhea as a young dog and has been on Eukanuba low residue diet her entire life since these problems emerged (18 - 24 mos.)  She is exhibiting pain in jumping up onto "her" chair, never jumps on the bed anymore and her right upper leg appears to be "wasted".   Nonetheless, she still enjoys a 3 mile walk each and every day without limping and is not overweight.  My vet took an x-ray of her hip and spine.  While the spine shows evidence of some arthritis, the hip appears unaffected.  What are we missing here?  I've changed her dog food to a completely organic brand (senior formula) but she continues to exhibit pain.  I've just started this regimen (only 1 1/2 weeks in) and have been giving her a supplement of DGP to help with the pain.  Should there be an x-ray of the entire leg, not just the hip, to check for bone cancer in the leg?

One of the things that stands out to me in this case is the "wasted" appearance of the leg, which I'm assuming is atrophy of the muscle.  When it happens bilaterally or in general muscle groups in multiple areas there can be a disorder of the muscle itself, as well as general causes of wasting such as kidney disease, cancer, and so on.  But when it happens very specifically in one limb, it is usually due to a lack of use of that limb.  When muscle is used it grows; when it is not used, it shrinks and deteriorates.  So if it's just her right thigh that's "wasted", it's probably an indication of a long-term lack of or decreased use of that leg even if you haven't seen a lot of limping.  Many dogs will ignore pain and discomfort when it's an activity that they really enjoy, such as walks and playing.  Pushing through the pain is one of the reasons we can see dogs that are otherwise uncomfortable be able to do some high-energy activities.

Most of the time when there is bone infection or cancer there will be a swelling of the bone that is visible or palpable.  In these cases you should certainly take further x-rays and likely a biopsy of the bone.  Without outward signs there may not be a strong indication to radiograph the rest of the leg.  And I think if it's this painful there would probably be more signs that you wouldn't need x-rays to see.  However, with a lack of other visible causes I think it certainly wouldn't hurt to check for subtle issues.

"Organic" or "inorganic" foods won't make a difference with joint pain.  Honestly, in my opinion, the "organic" food craze in humans and animals has very questionable health benefits compared to other foods.  But that's not the point of this discussion.  My point in Biscuit's case is that a switch from one maintinence food to another one, regardless of manufacturing or brand, will not have any significant outcome on pain or joint problems.  There is nothing about organic foods that will lower pain or aid joint function.

If this is related to arthritis (and such problems aren't always easily visible on x-rays), here is my typicall recommended approach.
1.  Have your pet at a normal weight.  In Biscuit's case this apparently isn't an issue.
2.  Use a food or supplement high in glucosamine and chondroitin.  Be aware that studies have shown some questionable results as to whether there is real benefit, though clinically most vets have seen cases that really are helped by it.  Not all supplements are created equal!  Just because the ingredients are in the formulation doesn't mean that they can be easily absorbed into the pet's system.
3.  Use good essential fatty acid supplements, especially omega-3.  There is strong evidence that these ingredients act as effective natural anti-inflammatories and can give benefit in arthritis and skin disorders.  However, you normally need very high levels.  Many people want to give a couple of fish oil capsules, and though this approach is in theory sound, in practice you can't get any benefit.  A 50 pound dog would need to take over 40 capsules per day to be strongly affected!  However, there are supplements and especially specific foods that have the necessary ammounts.  I have good personal experience with Royal Canin Mobility Support and Hill's J/D.
4.  An emerging supplement in arthritis is green-lipped mussel (a shellfish).  This is starting to show up in some foods and supplements and has some very promising results.  I know that Greenies recently starting making a treat with this as a main ingredient, but I don't have personal experience with it.
5. In bad cases, prescription pain medications should be used, though in an older dog you should have routine blood testing prior to starting on them.  Most non-steroidal anti-inflammatory drugs (NSAIDs) designed for dogs are safe and effective.  Talk to your vet about which one they normally use.
6.  Adquan is an injectible medication that has been shown to help rebuild joint surfaces, and can make a big difference in arthritis pain related to degenration of the joint.  This is another thing to talk to the vet about.

If these suggesitons don't help with Biscuit's pain, you may have to consider being referred to a speciality practice. They may want to do special studies on her spine and limbs to look for signs that you can't see on an x-ray.  You may need a myelogram (dye injected around the spinal cord) to see certain mild slipped discs between the vertebrae, or need MRIs or CT scans.  All of these things are expensive, but if the problem can't be controlled medically and nutritionally, may be the best way of finding the cause of the problem.

Good luck with Biscuit!