Elbow dysplasia is a common cause of front-leg lameness
in large-breed dogs. Breeds predisposed to elbow dysplasia include the
Golden Retriever, Labrador Retriever, English Setter, English Springer Spaniel,
Rottweiler, German Shepherd, Bernese Mountain Dog, Chow Chow, Chinese Shar-Pei,
Newfoundland, and others.
The elbow joint is composed of the humerus, which articulates with the
radius and ulna, and those two bones. The anconeal processunites with the ulna
at about 6 months of age. It forms a curved depression in the ulna. The
coronoid process forms part of the lower curved bone of the ulna.
Estrus, or heat, is the stage in a female dog's reproductive
cycle during which she becomes receptive to mating with males. At this time,
estrogen levels first increase and then sharply decrease, and mature eggs are
released from the ovaries. Ideally, your dog should be spayed before she enters
her first heat cycle.
Dogs with elbow dysplasia have one or more of the following inherited
developmental defects, which may occur singly or in combination: ununited
anconeal process, fragmented medial coronoid process, osteochondritis dissecans
of the medial condyle of the head of the humerus, and incongruity of growth
rate between the radius and ulna resulting in curvature of the radius. The
first three defects are related to osteochondrosis. The fourth is
related to an enlargement of the epiphyseal growth plate at the head of the
Signs of elbow dysplasia usually appear in puppies at 4 to 10 months of age,
but some dogs may not show signs until adulthood, when degenerative joint
disease starts. The signs consist of varying degrees of front-leg lameness that
worsens with exercise. Characteristically, the elbow is held outward from the
chest and may appear swollen.
The diagnosis is made using detailed X-rays of the elbow joint, taken in
extreme flexion. Radiologists are particularly interested in the appearance of
the anconeal process of the ulna. In a dog with elbow dysplasia, the anconeal
process has a rough, irregular appearance due to arthritic changes. Another
sign of dysplasia is widening of the joint space associated with a loose,
unstable joint. X-rays may be difficult to interpret before a pup is 7 months
of age. A CTscan may be required to demonstrate a fragmented coronoid
The OFA evaluates X-rays and maintains registries for dogs with elbow
dysplasia. Dogs must be 24 months of age or older to be certified by OFA,
although it accepts preliminary X-rays on growing pups for interpretation
Treatment: Medical treatment is similar to that described for Hip Dysplasia, page 392. Surgery is the treatment of
choice for most dogs. Several factors, including the age of the dog and the
number and severity of the defects, govern the choice of surgical procedure.
The more defects in the elbow, the greater the likelihood that the dog will
develop degenerative arthritis-with or without surgery.
Bone lengthening is a continuous process in which rapidly growing cartilage
at the ends of bones becomes calcified and is gradually incorporated into the
bone. Osteochondrosis is a disease caused by a defect in the calcification
process of this growing cartilage. In a dog with osteochondrosis, the cartilage
is calcified in an irregular instead of a uniform fashion. This creates areas
of uncalcified, defective cartilage over the ends of the bones. With stress on
the joint, the defective cartilage breaks into loose fragments called joint
mice. This process, which is accompanied by joint pain and swelling, is called