Osteochondritis Dissecans (OCD) can occur in any joint, with the shoulder, elbow, knee and hock (ankle) being the most common. As dogs grows, their bones lengthen, and portions of cartilage transition into bone. With abnormalities in this process, a section of cartilage may not complete this transition and instead becomes thickened. This atypical section of thick cartilage does not have adequate blood supply to survive. As the cartilage piece dies off, cracks develop from the deeper layers to the joint surface. Eventually, a flap of cartilage forms that may detach from the rest of the joint surface. Since joints must have smooth gliding surfaces to function properly, this OCD flap leads to inflammation and pain/lameness.
OCD is a multi-factorial process, meaning that both genetics and developmental components are involved. Common breeds include Border Collies, Great Danes, Irish Wolfhounds, Labradors, and Rottweilers. There is some evidence that rapid growth and calorie consumption and joint trauma as a puppy can increase OCD risk.
Most dogs will begin to show clinical signs by 1 year of age. In puppies, they may exhibit lameness that gradually increases over months, particularly with exercise. Their joints can become stiff and swollen. Mildly affected dogs may have a relatively normal puppyhood, only to be more impacted later in life as their osteoarthritis progresses in severity. This osteoarthritis results in ongoing cartilage changes and inflammation/damage to other joint structures including the joint capsule and adjacent bone. These changes often occur by 6 months of age, but dogs may not show clinical signs of discomfort until much later.
Diagnosis
- Orthopedic Examination & Gait Evaluation
- Radiographs (also known as X-rays) highlight the bones comprising the shoulder (or other) joint and can reveal the current extent of osteoarthritis. Larger distinct OCD lesions can be visible on radiographs, while smaller ones may be obscured by overlapping bone in the images. However, joint remodeling secondary to the OCD (osteoarthritis) is commonly seen on radiographs.
- Advanced Imaging (CT Scan or MRI) can provide a more sensitive 3D reconstruction of the joint as a non-invasive method to evaluate potential OCD.
- Arthroscopy is useful as both a diagnostic method and to facilitate treatment. Arthroscopy involves the introduction of a miniature video camera through small incisions to visualize joint structures on a magnified scale. After camera-assisted visualization, an additional small incision can be made for specialized instruments to surgically address the OCD.
Non-surgical options
These methods do not correct the OCD. However, they can minimize their effects and increase comfort. Also known as medical management, options include: physical therapy/rehabilitation, maintaining a lean body weight, modifying exercise (low-impact), anti-inflammatory medications, joint supplements, and joint injections.
Medical management does not have a high rate of success with OCD lesions and can lead to rapid progression of osteoarthritis. It is typically only recommended in those dogs that are poor anesthetic candidates.
Surgery
- Arthroscopy allows visualization of the OCD and removal of the flap, prevent further abnormal cartilage wear, and stimulate fibrocartilage formation to fill in the defect. Arthroscopy is typically performed in the shoulder, elbow, and stifle joints. The ankle can be approached arthroscopically or via an open arthrotomy depending on the size of the dog.
- In OCD lesions of a certain size in the shoulder and stifle, replacement of the defect with naturally occurring or synthetic cartilage (SynACART®) is possible. Details of these procedures will be discussed during your appointment with the surgeon if applicable to your dog.
Prognosis & Recovery
Prognosis can be variable depending on the location and the extent of the OCD lesions. With shoulder OCD, many dogs return to normal, comfortable activity after the post-operative recovery period (typically 4-6 weeks of activity restriction). However, while fibrocartilage is superior to the OCD flap being left in place, this fibrocartilage is inferior to normally occurring articular (joint) cartilage. Osteoarthritis will continue to progress in these dogs, although at a slower rate, after surgery and impact these patients later in life.