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Antebrachial Growth Deformities in Dogs

On occasion, a dog's front leg continues to grow well after the other has stopped, resulting in one normal-sized leg and another irregularly-sized leg. This is commonly referred to as an antebrachial growth deformity. When this occurs the shorter leg's bone may twist and bow, or it overgrows at the elbow. In either case, the result is misalignment of the bones. The tendency of a joint to stop growing seems to be a recessive trait in Skye Terriers. There is also the possibility of elbow joint misalignment in basset hounds and Lhasa Apsos.

Another front leg deformity which commonly occurs is called elbow dysplasia. It occurs when the point of the elbow and the muscular structure do not develop normally, and is most commonly seen in large and giant-breed dogs, especially Bernese Mountain Dogs, Golden Retrievers, Labrador Retrievers, and Rottweilers. Males are also more susceptible to the condition. This deformity becomes apparent at the fifth to the eighth month and is usually in both elbows.

Longer-limbed dogs are more likely to suffer deformities of the longer bones, whereas shorter-limbed dogs tend to develop more joint problems. The age of the animal when the deformity occurs will also affect the severity of the condition.

Symptoms and Types

• Bowed and twisted front leg
• One leg is longer than the other
• Lameness (which is especially apparent after exercise)

Causes

There are many potential causes for front leg deformities in dogs; some of the more common ones include:

• Trauma: This is most common cause; it may interfere with new cartilage production, resulting in a stoppage of bone elongation
• Osteochondrosis: A disturbance in the change of cartilage to bone; the cause of this disease is not completely understood, however, it is thought to have genetic, nutritional, and traumatic components
• Elbow malalignment syndrome: It tends to occur in chondrodysplastic breeds (e.g., Basset Hounds, Dachshunds, and Corgis)
• Nutritional deficiency: This issue is becoming less prevalent in dogs as as nutritional standards improve
• Congenital: This is rare in dogs; a dog with this form of deformity will have severely bowed front legs and a possible ankle dislocation

Diagnosis

Your veterinarian will order X-rays of the entire limb, including the elbow, to compare the lengths of the bones, and to determine whether the muscles in the elbow are attached. Other signs the veterinarian may look for in the X-rays to confirm antebrachial growth deformities are bone enlargement, inflammation of the entire bone structure, and flexor muscle spasms.