Osteochondritis Dissecans - OCD

Any dog that develops a limp that does not improve within fourty eight hours should be checked by a vetinarian.
In some cases especially if it is a young pup it can be OCD.

This is a disorder of immature long bones seen primarily in dogs , horses and even humans.
It is due to a various set of circumstances which include diet , trauma , genetics , body size and weight .
Growing long bones may develop cracks in the cartilage of the weight bearing surface .
these cracks may extend deep to the soft (cancellous ) bone beneath the cartilage and eventually a section of the joint cartilage will seperate from the underlying structure.

This cartilage flap varying in size from less tahn a quarter of an inch to over an inch in diameter then acts as an irritant in the joint.
Subsequent inflammation and attempts at healing lead to scar tissue and calcium deposits in the affected joint.

The normal humeral head has a very regular and smooth surface  which slides forward and backward under the joint surface of the scapula bone.
In effected dogs the smooth rear surface of the humerus head will have a pitted look and on Xray you will beable to see the cartilage flap .

the joint capsule is actually a sealed chamber that contains lubricating joint fluid . Any loose cartilage fragments  are trapped in this space and can create pain if wedged between the two bones forming the joint.
Plus there is inflamation and nerve irritation due to the fact the cartilage flap shouldnt be there.Most cases of OCD create low grade discomfort in the dog. There will be limping and the dog will attempt to rest and protect the effected joint.

Causes

There are  many theories as to the causes of this condition and as this disorder seems to be spontaneous and not so easy to predict it is impossible to say why some dogs get OCD and some dogs dont.
OCD almost always shows up in the "growth stage " of a young dog's life this is usually between six to nine months - hence the need for a high quality diet and not too much physical excercise  
Contributing factors may be -
overweight growing dogs  - an overweight pup is not a healthy pup
any physical impact on the limbs
constant jumping up and down especially off high surfaces - such as jumping out of the back of a car
constant jumping off high steps or stairways - it is an impact on soft joints when pup is jumping up and down.
Diet is a big problem  -
it is advisable to feed a high quality meat based diet  , high in protein and  low in carbohydrates.
avoid diets who have grain as their first main ingredient  , corn and wheat.
monitor the dogs weight and growth.

Rather than a cure there are a couple of treatments available .
The first direct approach is rest !
The dog requires complete confinement for a number of weeks where activity and jumping will be kept to a mininmum.
After four to ten weeks of confinement there is about a 60 percent chance the defect will heal and the dog may return to normal activity.

If however healing does not occur surgery is the other option depending on where the OCD occurs its usually a case of scraping out the effected particles of loose cartilage and flushing the
 joint , it is then up to the owner to ensure the aftercare and rest is adhered too.before normal activity is resumed.