Osteochondritis

Osteochondritis dissecans (sometimes spelled dessecans, and abbreviated "OCD") is a painful condition within a joint of the body in humans or animals, in which fragments of cartilage or bone have become loose within a joint, leading to pain and inflammation. These fragments are sometimes referred to as "joint mice" due to a squeaking sound sometimes resulting from the joint. Specifically, OCD is a type of osteochondrosis in which a lesion has formed within the cartilage layer itself, giving rise to secondary inflammation. It has a complex etiology, and can be caused by genetic, hormonal, environmental and nutritional factors.

In animals, OCD is considered a developmental and metabolic disorder related to cartilage growth and endochondral ossification. Osteochondritis itself signifies the disturbance of the usual growth process of cartilage, and OCD is the term used when this affects joint cartilage causing a fragment to become loose.^[1] OCD in animals is "well recognized but poorly understood".

OCD can often be treated surgically.

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General

OCD occurs when a loose piece of bone or cartilage separates from the end of the bone, often because of a loss of blood supply and insufficient amounts of calcium. The loose piece may stay in place or slide around making the joint stiff and unstable. OCD in humans most commonly affects the knees or ankles, but can also affect other joints such as the elbow. If a serious injury occurs in this area, the bone around it will supply it with as much calcium as possible to try and fix the loose piece of bone. This often results in a calcium build up around the loose piece. This build up is surgically removed most of the time.

The term "dessicans" refers to the "creation of a flap of cartilage that further dissects away from its underlying subchondral attachments (dissecans)" [1]

OCD has been associated both to too little, and too much, calcium in the body.^{[citation needed]}

In humans

OCD is a relatively rare disorder. It commonly occurs in boys and young men from 10-20 years of age while they are still growing. As girls become more active in sports, it is becoming more common among them as well. Prevalence In knee, 30–60 cases per 100,000 population

Diagnosis

To determine whether your pains are osteochondritis dissecans, an MRI or X-Ray can be performed to show whether the loose piece of bone is still in place. In specific cases if caught early enough, a harmless dye will be injected into your blood stream to show where the calcium will most likely continue to build up. Doing this makes the removal process much easier.

In animals

According to Lowchens of Australia:^[2]

"Medium and large breeds are most commonly affected including the Rottweiler, Labrador Retriever, Golden Retriever, German Shepherd, Bernese Mountain Dog, Newfoundland, St. Bernard and Great Dane. OCD has also been reported in the cat. Joints commonly affected by OCD include the shoulder, elbow, stifle, and hock. Joints are often affected bilaterally."

The problem develops in puppyhood although often subclinically, and there may be pain or stiffness, discomfort on extension, or other compensating characteristics. Diagnosis is via scans such as X-ray, arthroscopy, or MRI, and treatment is often surgical although the best method remains open to debate.

Because an animal may compensate for painful forelegs by misuse of rear legs, there is a possibility that this condition can be masked by other skeletal and joint conditions such as hip dysplasia.

See also

• Osteochondrosis
• Osteochondropathy

Animal

• Fully detailed UPENN page on canine OCD
• Lowchen's resource and links page
• The Pet Center: OCD page

References