Causes of elbow dysplasia
Elbow dysplasia includes the following conditions: fragmented medial coronoid process (FCP), osteochondritis dissecans (OCD), elbow incongruity, ununited anconeal process, and ununited medial epicondyle.
FCP is a small piece of bone on the inner side of the joint, which has broken off the ulna bone. This fragment of bone irritates the lining of the joint and grinds off the cartilage of the adjacent humerus (similar to a pebble in your shoe that is irritating your foot).
Ununited anconeal process is a condition in which a part of the ulna bone, called the anconeal process, fails to fuse with the main ulna bone during the growth phase. Normally this bony process fuses to the ulna bone by 20 weeks of age.
OCD is a condition in which a piece of cartilage becomes partially or fully detached from the surface of the humerus bone. This results in inflammation of the lining of the joint and subsequent pain.
Elbow incongruity is a poorly fitting joint, which results in excessive wear of the cartilage within the joint. The result is arthritis of the elbow.
The ununited medial epicondyle is a piece of bone, which has separated from the medial (inner) side of the humerus bone. This is the site where a group of forelimb muscles attaches. In the young puppy, the bone is soft and made of cartilage. If this region fails to develop into bone within the normal timing of development, the muscles may pull this part off the humerus bone. Subsequently, this dislodged epicondyle forms into a loose piece of bone that rubs on the inner side of the elbow and on the ulnar nerve.
X-rays of the elbow joint will allow your pet’s doctor to make a diagnosis of ununited anconeal process, ununited medial epicondyle, and sometimes OCD. CT scan and arthroscopic surgery of the elbow joint are usually the best diagnostic tools used to diagnose FCP, OCD and incongruity of the elbow joint.
Arthroscopic surgery is the recommended treatment for elbow conditions. Two very small incisions are needed to perform the surgery, which means less pain for your companion than traditional open surgery. The joint is examined with a very thin telescope to confirm the diagnosis. If an OCD cartilage flap is present, it is removed from the joint. The OCD bed is trimmed at the edges, and small holes are made in the OCD bed so that healing will occur faster. If an FCP is present (see figure 4), it is removed with a combination of an arthroscopic shaver and small instruments. If an ununited anconeal process is present, the bony fragment is removed via a 2 cm incision made on the side of the joint. The area of the medial coronoid is examined with the arthroscope and removed if it is fragmented. If an ununited medial epicondyle is determined to be the problem, the joint is examined with the arthroscope, as some of these patients have a concurrent fragmented coronoid process; then the ununited medial epicondyle will be removed through a separate 3 cm incision. Elbow incongruity is not treated surgically if it is mild. If this problem is significant, the ulna bone is cut just below the elbow joint to allow the joint to fit better.
Arthroscopic elbow surgery is currently one of the best methods available to both diagnose and treat elbow conditions. Although all dogs that have elbow dysplasia develop arthritis, surgical intervention with arthroscopy can help decrease pain within the joint.
For more information on this subject, speak to the veterinarian who is treating your pet.