shouldering the burden: osteochondritis dissecans
Our large breed canine friends are prone to some orthopedic conditions that their smaller counterparts are safe from, and one of these conditions is called Osteochondritis Dessicans, or OCD for short.
In dogs with the orthopedic condition OCD, there is a disturbance in the development of the cartilage layer of growing bones. Immature cartilage fails to turn into bone, resulting in a thick layer of cartilage at the outer surface of the bone in some joints of the body. This thickened layer of cartilage is fragile and more susceptible to damage than normal cartilage.
Normal stresses to the joint, trauma, and other unknown mechanisms can all cause damage to the thickened cartilage. Usually these mechanisms result in a free flap of cartilage that peels away from the surface of the bone in the joint. This flap can remain attached, may occasionally be resorbed, or may break free and become what is known as a “joint mouse.” Joint mice float freely in the joint cavity and in addition to causing discomfort, they can grow in size, worsening the condition.
Whether the cartilage flap remains attached to the bone or becomes a joint mouse, it causes discomfort to affected dogs and will cause arthritic changes to the joint over time. Multiple joints can be affected, such as the stifles, hocks, and elbows, but the most common place for OCD lesions is the shoulder.
Affected dogs are generally dogs who will weigh over sixty pounds at maturity, including many of the most popular breeds in the United States. Golden Retrievers, Labrador Retrievers, and German Shepherds are prone to OCD as are all other large and giant breed dogs. Clinical signs are seen as early as five months of age, and male dogs are two to three times more likely to have OCD than females of the same breed. In many cases, OCD lesions are bilateral, even if clinical signs are only detected on one side.
The major clinical sign seen in dogs with OCD is lameness, which can be sudden onset or can be insidious in nature. Because the lameness generally goes away with rest, many owners are reluctant to pursue veterinary care at first. But over time, as the lesion gets worse, clinical signs also progress, leading owners to seek out medical help for their painful pooch.
Veterinarians can often diagnose OCD lesions by taking a radiograph of the affected joint. Because positioning is key when diagnosing OCD lesions, your veterinarian may want to sedate your dog before taking an x-ray. This minimizes stress on both the patient and the staff. If x-rays fail to yield a diagnosis, a CT scan can be pursued. Another option for diagnosing OCD lesions is arthroscopy, which can be used both as a diagnostic tool and a therapeutic tool if the operator is ready to also remove the offending cartilage flap at the same time.
Conservative treatment for dogs with OCD will likely start with cage rest and anti-inflammatories, though this type of treatment is often unrewarding. Surgical intervention is preferred when conservative treatment fails. Surgery, either open or arthroscopic, is performed to remove loose cartilage pieces and to stimulate the bone surface defect to heal. Post-operative care will require a short period of rest and possibly some physical therapy, but the results are rewarding, especially in cases of shoulder OCD where most patients are returned to normal function without lameness. Because OCD occurs in young growing dogs, this means a lifetime of pain free activities!
If your large breed puppy comes up lame, OCD may be to blame. Keep a close eye on his symptoms and get in to see your veterinarian if they persist!