Osteochondritis dissecans (OCD) affects young, large-breed dogs and causes forelimb lameness. It is a condition in which a region of the cartilage surface, usually the size of a dime, fails to undergo normal development. This region of cartilage becomes thicker than normal. Because nutrients penetrate cartilage by diffusion, the deep part of the abnormal cartilage does not get nourished, as it is too thick. Subsequently, some of the cartilage cells die off which results in weakening of the cartilage. This area of cartilage then separates from the underlying bone in the form of a cartilage flap. Sometimes the cartilage flap becomes detached from its bed and falls into a pouch of the joint (called the cul de sac of the shoulder). Occasionally a fragment of the OCD flap will migrate down the sheath of the biceps tendon (which communicates with the shoulder joint) and causes inflammation of the tendon’s sheath.
Signs and diagnosis
A diagnosis of OCD is based on findings of X-ray images, in addition to finding signs of pain upon flexion or extension of the shoulder joint. A side view X-ray of the shoulder usually reveals evidence of OCD (flattening of the humeral head).
Traditional surgery used to treat shoulder OCD involves making a sizeable incision over the side of the shoulder in order to remove the OCD flap. This procedure can have similar results to arthroscopic surgery, but has some disadvantages. First, traditional surgery is more painful than arthroscopic surgery. Second, all areas of the joint cannot be seen using traditional surgery; thus small loose pieces of cartilage may be missed. These small free-floating cartilage fragments can result in continued inflammation of the joint.
Arthroscopic surgery is the treatment of choice for OCD. Two very small incisions are needed to perform the surgery, which means less pain for your companion. The OCD flap, which is frequently attached to the bone by a thin stalk, is removed with special instruments.
Free-floating pieces of cartilage are removed in order to minimize the risk of inflammation of the biceps tendon.
Arthroscopic shoulder surgery is currently one of the best methods available for shoulder OCD. About 90 to 95% of dogs that undergo this surgery can expect to return to athletic activity within six months.
For more information on this subject, speak to the veterinarian who is treating your pet.