A moveable joint
at the intersection of two or more bones is held together by a joint
capsule and ligaments. It is cushioned by cartilage on the bone ends
and lubricated by joint fluids. Arthritis occurs when any of
these components break down. Although old age wear and tear is probably
the most common cause, there are many others. Infectious causes include
bacteria which reach the joints by way of bite wounds or other punctures
and those that arrive by way of the blood such as Borrelia (Lymes Disease)
and “joint ill” from the umbilicus in new born puppies, kittens and
foals. Fungal infections may also be seen in joints. Immune mediated
joint disease such as rhematoid arthritis is uncommon but is the first
diagnosis considered when multiple joints are suddenly affected by swelling
consider Lymes arthritis to be an immune mediated after effect of
Borrelia infection as opposed to being caused by the infection itself.
Ruptured cruciate ligament of the knee is a common injury in middle
aged overweight dogs. Because it occurs with minimal trauma in dogs,
investigations are underway to determine if there may be an immune
component to this ailment. Infectious and immune mediated joint disorders
are suggested by the presence of fever, swelling in one or more joints,
and severe lameness or reluctance to move. The diagnosis is based
on blood tests, xrays, and laboratory examination of joint fluid.
In rare cases a biopsy may be necessary. Appropriate treatment—antibiotics
or steroids--may cure or control these conditions but unless diagnosis
and treatment happen early there may be permanent joint damage and
arthritis later in life. Any moveable joint can be affected by traumatic
dislocation, but the hip is the most frequently involved. Sometimes
dislocations can be replaced under anesthesia by simple manipulation,
but often surgery is needed to reduce luxations, and pins or screws
may have to be used to hold the joint together.
Surgery is also
a treatment option for some joints which develop improperly during
growth. Once again the hip is the joint most likely to be affected.
But besides hip dysplasia, there are a number of other congenital
or developmental joint disorders. Lack of fusion of growth centers
in elbows causes an ununited anconeal process or fragmented coronoid
processes called “elbow dysplasia”. Uneven bone growth called osteochondritis
dessicans (OCD) occurs most often in the shoulders but may be seen
in many other joints. It can lead to broken off pieces of cartilage
which calcify in the joint. These joint “mice” feel to the dog like
a rock in your shoe. A circulatory disorder in the hip of toy dogs
causes severe hip deformation called Legge-Perthes syndrome. The knee
joint is very complex with three major bones—the femur, tibia, and
fibula; and three minor bones—two fabellae and the patella. Growth
deformities, especially related to displaced or dislocating patellas,
Since early detection
and treatment of joint disorders delays progression of arthritis and
prevents a great deal of discomfort it is important to ask your veterinarian
about the appropriate time to evaluate your puppy for joint disease.
Palpation and/or xrays can detect problems before lameness begins.
Persistent or recurrent limping, an unusual gait or poor muscle development
in young growing dogs should be investigated. If early arthritis or
its predisposition can be detected there are several things that can
be done. Whenever possible, surgical correction of the defect should
Cost on these
operations ranges from several hundred to a few thousand dollars depending
on the type of operation. There are several different types of operations
available for hip dysplasia and knee deformities. Most should be performed
by a specialist or at a university but some may be performed by a
general practice veterinarian. Such surgery on a 4-8 month old dog
can buy years of pain free existence.
If surgery is
not an option, keeping the dog thin and providing daily exercise are
very helpful. Exercise should be walking or swimming daily, not chasing
a frisbee on weekends and being a couch potato all week. (Does this
sound like advice our doctors give us?)
agents (chondro=cartilage) can be used lifelong. These include
an injectable drug given once a month, and glucosamine with or without
chondroitin. Glucosamines are oral “neutraceuticals” sold as food
supplements, not FDA approved drugs. Their usefulness has been shown
by years of experience as opposed to controlled drug trials. Because
there are many brands and their production is not regulated, it is
important to check with a veterinarian to make sure you get one with
the proper strength, dose and purity.
strengthen and heal cartilage and improve the lubricating ability
of the joint fluid. They can be used even in cases where arthritis
is quite advanced but for improvement to occur they should be given
in high doses for a short induction period followed by a lower maintenance
for more advanced cases is non steroidal anti inflammatory drugs (NSAIDS).
This family includes aspirin, phenylbutazone (a horse medication),
and ibuprophen. The two NSAIDS which are approved for dogs at this
time are Rimadyla and Etogesica. Unlike human drugs, they have been
shown to be generally safe when given over a long period of time,
and their direct pain relieving effects make them especially useful
for more immediate relief. Your veterinarian may advise periodic monitoring
for signs of stomach ulcers or liver disease as these may occur in
very rare cases with these drugs.
been used to relieve chronic arthritic pain, but it should be performed
only by someone trained and experienced in its use. There are other
supplements such as super oxide dismutase, a free radical scavenger,
which may be of use in selected cases.
A special note
to cat owners. Although cats are less likely to develop arthritis
than dogs, bite wounds and other traumatic joint injuries do occur.
Both hip dysplasia and knee cap luxations have also been seen in cats.
In addition, cats are now living longer, and are more inclined to
be overweight, so we can expect to see an increase in arthritis in
There are currently
no NSAIDS which are safe for use in cats. Neither tylenol (acetaminophen),
nor aspirin nor either of the new dog NSAIDS should be used for arthritis
in cats. The chondroprotectives are safe in cats but there is less
data to demonstrate effectiveness. The simple application of heat
by way of heating pads or hot compresses can temporarily relieve discomfort.
If you know your
pet is arthritic, do not assume that it doesn’t hurt if it is not
limping. The gradual onset of arthritis pain accustoms the pet to
higher and higher levels of discomfort. If two or more legs are equally
bad it is impossible to limp on one leg without making another leg
hurt worse. Look for general stiffness, reluctance to use stairs,
lameness that improves as the animal moves around, and muscle atrophy.
Many owners of older pets are pleasantly surprised at how much more
active the pet becomes when arthritis treatment is begun.