Osteochondritis Dissecans
by Joe Bodewes, DVM
Drs. Foster &; Smith, Inc.
Veterinary Services Department
Osteochondritis dissecans, commonly known as OCD and osteochondrosis
dessicans, 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 per cent 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?
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Trauma
to the joint, hereditary factors, rapid growth, restricted blood flow to
the cartilage, and nutrition contribute to the formation of OCD lesions.
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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 don't 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
Brinker, W.; Piermattei, DL; Flo, GL. Handbook of Small Animal Orthopedics
and Fracture Treatment. Saunders, Philadelphia, PA; 1983
Compendium. "Osteochondritis Dissecans of the Canine Tarsal Joint,"
Compendium; July 1994
Harari, J. The Veterinary Clinics of North America, "Osteochondrosis".
Saunders, Philadelphia, PA; 1998
