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Canine Osteochondritis Dissecans
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This is a
disease of the joint cartilage formation, which is an element of elbow
dysplasia, but it can affect other joints such as shoulder and stifles.
OCD results from degeneration
of the bone underlying the joint cartilage. During the growth
phase,
at aproximately six to nine months of age, affected dogs begin to limp
and
have painful joints often without a history of injury. Often the
shoulders, hocks or elbows are affected and muscle loss can result from
lameness and favouring the opposite leg, which results in worsening of
the limp.
Rest can be effective, but difficult in young dogs. The problem is
diagnosed using an x-ray and sometimes a fibre optic arthroscope is
used to allow the surgeon to see directly into the joint.
Occasionally the problem may appear to right itself, but surgery is
often required to remove the damaged cartilage. Though lameness
clears up three to six months after surgery, arthritis usually
develops. Pain relief is
often needed and sometimes joint surgery is required. It tends to
affect rapidly growing large breed dogs.
Osteochondritis
Dissecans
Veterinary & Aquatic Services Department, Drs.
Foster & Smith, Inc.
Osteochondritis dissecans,
commonly known as OCD and osteochondrosis dissecans, is a disease of
the cartilage that affects the joints in a dog’s body. In any joint in
the
body two bones come together and movement is allowed between them.
Where
the two bones meet, an exceptionally smooth area of cartilage covers
their
surfaces. This acts as a cushion and protects the underlying bone. If
anything
disrupts this smooth cartilage surface, movement of the joint becomes
painful.
In a dog with OCD, this cartilage is damaged or grows abnormally.
Instead
of being attached to the bone it covers, it separates or cracks,
causing
great pain. In some cases, small pieces of cartilage break off and
float
free in the joint. These pieces of cartilage do not die, but rather
continue
to grow and increase in size. These are known as joint mice.
Approximately
15% of all dogs will develop OCD. This article will cover the disease
and
its treatment and will explore some of the suspected causes.
Who gets OCD?
OCD is primarily a problem in large or giant breed dogs. It has been
reported in small dogs and cats, though it is not very common. It
affects male dogs 2 to 5 times as frequently as females, most likely
due to the males’ larger size and increased stress on the joint. It
generally occurs when the animal is between 4 and 8 months of age,
though it can show up in older dogs. There are several breeds that
despite being larger breeds, have decreased incidences of the disease
including the Doberman Pinscher, Collie, and Siberian Husky.
What are the symptoms of OCD?
The symptoms are lameness in the affected limb. Some dogs have a barely
noticeable limp and others are unable to bear any weight on the leg.
The lameness tends to worsen after periods of exercise and improves
after rest. Seventy four percent of the cases of OCD occur in the
shoulder joint, 11% in the elbow, and 4% in the hock. When it affects
the front shoulder, a shortened forelimb stride may be noted due to
reluctance to flex and extend the shoulder joint. Occasionally, the
disease will affect both limbs simultaneously and the dog may be
reluctant to move.
How is OCD diagnosed?
Diagnosis is based on history, physical exam, and radiographs (x-rays).
On physical exam, we notice joint pain. For instance, most healthy dogs
show no resistance when their shoulder joint is fully flexed and
extended. However, if they have an OCD lesion in their shoulder, they
may resist shoulder manipulation and may even cry out in pain when it
is attempted. In addition, this flexion and extension of the shoulder
joint may worsen the lameness.
Radiographs of the affected joint are taken to confirm the diagnosis.
The dog is often sedated so that full relaxation of the joint can be
obtained. Several views of the affected joint and the healthy joint on
the other
side are taken for comparison. The separations of the cartilage or
joint
mice are often identified on radiographs. If the radiographs are not
confirmatory but OCD is still suspected, radiographs may be taken again
in 2 to 3 weeks.
What causes the formation of OCD?
Trauma to the joint, hereditary factors, rapid growth, restricted blood
flow to the cartilage, and nutrition contribute to the formation of OCD
lesions.
The cause of OCD is considered to be multifactorial. It is thought
that there are several factors that contribute to the formation of OCD
lesions including trauma to the joint, hereditary factors, rapid
growth,
restricted blood flow to the cartilage, and nutrition.
Trauma, whether chronic or acute, may contribute to the formation of
OCD lesions. Injury to the surface cartilage may lead to the separation
of the cartilage from the bone or cause a decrease in blood supply that
leads to cartilage flap formation.
It appears that there is a genetic link between parents and offspring
and the formation of the disease. Certain breeds and genetic lines are
much more likely to develop the disease. Careful screening of parents
against this disease is recommended during the selection of all
breeding stock.
The disease usually occurs during periods of rapid growth. Therefore,
it has been suggested that nutrition that creates rapid growth may lead
to the increase in incidence of the disease. It has been recommended
that animals that are susceptible to the disease be fed a diet that is
lower in
protein and fat, or that they are fed in a limited manner to allow
steady even growth during the first year of life. This theory may have
merits, but
more specific studies need to be done before any general
recommendations can be made.
How is OCD treated?
There are currently two ways to treat OCD; conservative medical
treatment or surgical removal of the lesion. Conservative treatment may
be indicated for dogs that have early mild symptoms of OCD or where a
specific lesion cannot be identified on radiographs. Conservative
treatment consists of
strict rest for 4 to 8 weeks. Leash walking is permitted but no running
or playing is allowed. Anti-inflammatories and painkillers such as
buffered
aspirin or carprofen (Rimadyl) may be indicated. (Do NOT give your cat
aspirin
unless prescribed by your veterinarian.) In addition, the use of
glucosamine/chondroitin products has been suggested, yet there are no
current studies that confirm their beneficial use in this particular
disease. Conservative treatment may be difficult in young active
puppies who may still need to undergo
surgery, if the symptoms do not improve.
Surgery is indicated in animals that show severe symptoms, in cases
where large lesions are identified on radiographs, or when conservative
treatments fail. The surgery is very straightforward. The affected
joint is opened and the offending flap, defect, or joint mouse is
removed. There is a very high success rate for surgery and most animals
recover fully without any further problems.
How is OCD prevented?
Prevention consists of careful selective breeding that avoids the
breeding of animals with a history of OCD. Young large and giant breed
dogs should not undergo strenuous activity, particularly jumping
activities. Housing on hard concrete surfaces has been linked to
increased OCD lesions in pigs and may also contribute to problems in
the dog. Providing a good balanced diet that promotes even sustained
growth is also recommended. There are
currently many large breed puppy foods on the market made specifically
to help reduce the incidence of bone formation problems. While there
has
been no evidence that these diets actually reduce the incidence of this
disease as compared to other commercial puppy foods, future studies
might
support their use.
Summary
OCD is a cartilage problem that affects young large and giant breed
dogs. It is due to several factors including genetics, trauma, rapid
growth, and nutrition. Treatment is either conservative including
strict rest,
or surgical removal of the damaged cartilage. Prevention is aimed at
good
genetic selection, reduced activity, and careful feeding.
References and Further Reading
Brinker, W.; Piermattei, DL; Flo, GL. Handbook of Small Animal
Orthopedics and Fracture Treatment. W.B. Saunders Co. Philadelphia, PA;
1983.
Compendium. 'Osteochondritis Dissecans of the Canine Tarsal Joint,'
Compendium; July 1994.
Harari, J. The Veterinary Clinics of North America, 'Osteochondrosis.'
W.B. Saunders Co. Philadelphia, PA; 1998.
Copyright
© 1997-2009, Foster & Smith, Inc. All Rights Reserved.
Reprinted as a courtesy and with permission from PetEducation.com (
http://www.PetEducation.com)
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reprinted with kind permission from Josie Pitterle Article Reprint
Coordinator Drs. Foster and Smith
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The above information is simply
informational. It's intent is not to replace the advice of a
veterinarian nor to assist you in making a diagnosis of your pet.
Please consult with your own veterinarian for confirmation of any
diagnosis. Your pets life may depend on it.