Osteochondritis Dissecans (OCD) in Dogs

Excess Cartilage and Deficient Bone Growth in Dogs

Endochondral ossification is a normal bone growth process by which cartilage is replaced by bone in the early development of the fetus. Osteochondrosis is a pathological condition in which normal endochondral ossification, the metamorphoses of cartilage to bone, is disturbed. The disturbance is often due to a disruption in the blood supply to the bone. The result is retention of excessive cartilage at the site as the process of endochondral ossification is halted, but cartilage continues to grow. The end result is abnormally thick regions of cartilage that are less resistant to mechanical stress, as opposed to the stronger and denser bone.

Large and giant breeds, including great Danes, Labrador retrievers, Newfoundlands, rottweilers, Bernese mountain dogs, English setters, and old English sheepdogs are predisposed to this condition.

Symptoms and Types

• Lameness (most common symptom)
• Onset of lameness may be sudden or gradual, and may involve one or more limbs
• Lameness becomes worse after exercise
• Unable to bear weight on affected limb
• Swelling at joints
• Pain in limb, especially on manipulation of joints involved
• Wasting of muscles with chronic lameness

Causes

• Unknown
• Appears to be genetically acquired
• Disruption in supply of blood to the bone or through the bone
• Nutritional deficiencies

Diagnosis

You will need to give a thorough medical history of your dog’s health, onset of symptoms, and any information you have about your dog’s parentage. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. The results of these tests are often within normal ranges in affected animals, but they are necessary for preliminary assumptions of your dog’s overall health condition.

Your veterinarian will examine your dog thoroughly, paying special attention to the limbs that are troubling your dog. Radiography imaging is the best tool for diagnosis of this problem; your veterinarian will take several x-rays of the affected joints and bones to best discern any abnormalities. The radiographs may show details of lesions and abnormalities related to this disease. Computed tomography (CT-scan) and magnetic resonance imaging (MRI) are also valuable diagnostic tools for visualizing the extent of any internal lesions.

Your veterinarian will also take samples of fluid from the affected joints (synovial fluid) to confirm involvement of the joint and to rule out an infectious disease that may be the actual cause of the lameness. More advanced diagnostic and therapeutic tools like arthroscopy may also be used. Arthroscopy is a minimally invasive surgical procedure which allows for examination and sometime treatment of damage inside the joint. This procedure is performed using an arthroscope, a type of endoscope inserted into the joint through a small incision.