Causes of Elbow Dysplasia
Elbow dysplasia in dogs is widely considered to be primarily a genetic developmental disease. It often is associated with rapid growth and a high protein diet in young, large and giant breed dogs. Elbow dysplasia can be caused by one or more of four distinct but often related hereditary conformational abnormalities. These are:
- Ununited anconeal process (UAP). The anconeal process is a bony structure that normally unites with the upper end of the ulna by 6 months of age.
- Fragmented coronoid process (FCP; FMCP). The coronoid process is part of the lower ulna bone
- Incongruity in the growth rates of the radius and ulna (radio-ulnar incongruence. This incongruity results in abnormal curvature of the radius bone; and
- Osteochondritis dissecans (OCD) of the inner part of the head of the humerus (called the medial humeral condyle).
The humerus is the long bone in a dog’s upper front legs which connects the shoulder and elbow joints. The radius and ulna are the two long bones in a dog’s lower front legs connecting the elbow and wrist (carpus) joints. The specifics of these four abnormalities and the detailed anatomy of the elbow joint are beyond the scope of this article. However, owners should recognize that elbow dysplasia can be caused by one or a combination of these developmental defects and can occur in one elbow (unilateral elbow dysplasia) or in both (bilateral elbow dysplasia). Bilateral elbow dysplasia occurs in about half of dogs with this disorder. Most experts agree that there is a strong genetic component to elbow dysplasia. Other possible contributing factors are trauma, hormonal imbalances, poor nutrition, excessive protein in the diet of young dogs, excessively rapid growth, rapid weight gain and congenital conformational defects.
Prevention of Elbow Dysplasia
Rapid weight gain and accelerated growth in large and giant breed young dogs is one of the well-recognized contributors to elbow dysplasia. Owners of large breed puppies must pay careful attention to their dog’s nutrition and should not feed a diet that is overly high in protein or calories, so that rapid growth and weight gain are not encouraged. A veterinarian and the puppy’s breeder are in the best position to advise owners about an appropriate diet for their young dogs. Many high-quality dog foods have been developed specifically to support the growth and nutritional needs of large breed puppies and are increasingly widely available from veterinarians and pet food retailers. Most reputable breeders discourage breeding dogs that are diagnosed with elbow dysplasia, or repeating the breeding of a sire and dam that previously produced dysplastic puppies.
Elbow dysplasia is one of the most common causes of elbow pain and front limb lameness in dogs.