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Elbow dysplasia

This article pertains to elbow dysplasia in the dog.

Elbow dysplasia is a condition involving multiple developmental abnormalities of the elbow-joint. It is a common condition of certain breeds of dogs. Most developmental elbow abnormalities are related to osteochondrosis (OCD), which is a disease of the joint cartilage. Osteochondritis dissecans refers to separation of a flap of cartilage on the joint surface.

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Causes

In OCD, the normal change of cartilage to bone in the development of the joint fails or is delayed. The cartilage continues to grow and may split or become necrotic. The cause is uncertain, but possibly includes genetics, trauma, and nutrition (including excessive calcium and decreased Vitamin C intake).^[1]

The disease

OCD lesions are found in the elbow at the medial epicondyle of the humerus. Specific conditions related to OCD include fragmentation of the medial coronoid process of the ulna (FMCP) and an ununited anconeal process of the ulna (UAP). All types of OCD of the elbow are most typically found in large breed dogs, with symptoms starting between the ages of 4 to 8 months.^[1] Males are affected twice as often as females. The disease often affects both elbows (30 to 70 percent of the time), and symptoms include intermittent lameness, joint swelling, and external rotation and abduction of the paw.^[2] Osteoarthritis will develop later in most cases.

UAP is caused by a separation from the ulna of the ossification center of the anconeal process. FMCP is caused by a failure of the coronoid process to unite with the ulna. OCD of the medial epicondyle of the humerus is caused by disturbed endochondral fusion of the epiphysis of the medial epicondyle with the distal end of the humerus, which may in turn be caused by avulsion of the epiphysis.^[3]

Diagnosis and treatment

Diagnosis is through x-rays and arthroscopy. In cases with significant lameness, surgery is the best option, especially with UAP. However, conservative treatment is often enough for cases of FMCP and OCD of the medial humeral epicondyle. The dogs are exercised regularly and given pain medication, and between the ages of 12 to 18 months the lameness will often improve or disappear.^[1] Control of body weight is important in all cases of elbow dysplasia, and prevention of quick growth spurts in puppies may help to prevent the disease. Surgery for FMCP consists of removal of cartilage and bone fragments and correction of any incongruity of the joint. Reattachment of UAP with a screw is usually attempted before the age of 24 weeks, and after that age the typical treatment is removal of the UAP.^[4] Without surgery, UAP rapidly progresses to osteoarthritis, but with FMCP osteoarthritis typically occurs with or without surgery. Osteoarthritis is also a common sequela of OCD of the humerus despite medical or surgical treatment.^[4]

The Orthopedic Foundation for Animals in the United States will grade elbow X-rays of dogs intended for breeding.

Commonly affected breeds

UAP

German Shepherd Dog
Labrador Retriever
Basset Hound
Newfoundland
Shar Pei
Chow Chow
English Setter
Golden Retriever
Mastiff
Pomeranian
Rottweiler
Saint Bernard^[5]

FMCP

Basset hound
Bouvier des Flandres
Bullmastiff
Chow Chow
German Shepherd Dog
Golden Retriever
Gordon Setter
Irish Wolfhound
Labrador Retriever
Mastiff
Newfoundland
Rottweiler
Saint Bernard^[5]

OCD of the medial humeral epicondyle

Labrador Retriever
Chow chow
German Shepherd Dog
Golden Retriever
Great Dane
Labrador Retriever
Newfoundland
Rottweiler^[5]

Elbow incongruity

A combination of FMCP, UAP, and OCD of the medial humeral epicondyle is seen in the Bernese Mountain Dog. This is known as elbow incongruity, and it may be caused by abnormal development of the trochlear notch of the ulna.^[1]

References

^ ^a ^b ^c ^d Ettinger, Stephen J.;Feldman, Edward C. (1995). Textbook of Veterinary Internal Medicine, 4th ed., W.B. Saunders Company. ISBN 0-7216-6795-3.
^ Hazewinkel, H.A.W. (2003). Elbow Dysplasia; Clinical Aspects and Screening Programs. Proceedings of the 28th World Congress of the World Small Animal Veterinary Association. Retrieved on 2006-08-24.
^ Elbow Dysplasia. The Merck Veterinary Manual (2006). Retrieved on 2007-02-04.
^ ^a ^b Demko J, McLaughlin R (2005). "Developmental orthopedic disease". Vet Clin North Am Small Anim Pract 35 (5): 1111-35, v. PMID 16129135.
^ ^a ^b ^c LaFond E, Breur G, Austin C (2002). "Breed susceptibility for developmental orthopedic diseases in dogs". J Am Anim Hosp Assoc 38 (5): 467-77. PMID 12220032.