There cannot be a worse and sadder diagnosis than that of limb and joint defects made in a puppy or young dog. Puppies and young dogs love running, jumping, playing and rolling. But joint diseases such as elbow dysplasia can prevent all this. Elbow dysplasia is a developmental disease of the canine elbow which includes a group of different joint abnormalities having in common their anatomical location (the elbow) and their developmental origin.
Before describing the different conditions grouped under the name of elbow dysplasia, it may be useful to recall the salient points of the anatomy of the canine elbow joint, as well as the bone components of the elbow that can be involved in these process. The canine elbow joint consists of three joints: 1) the humeroradial joint, between the distal, or lower, end of the humerus and the proximal, or upper, end of the radius; 2) the humeroulnar joint, between the distal end of the humerus and proximal end of the ulna; and 3) the radioulnar joint between the proximal ends of the radius and the ulna, respectively. Three portions of the bones participating in the formation of the elbow joint are involved in the development of elbow dysplasia: 1) the anconeal process of the ulna, which is the most cranial proximal aspect of the ulna articulating with the humerus; 2) the humeral condyle, which is the distal aspect of the humerus articulating with both the radius and ulna; and 3) the coronoid process of the ulna, which provides the majority of the joint surface contact between the humerus and the ulna.
A developmental abnormality of any of the bone structures mentioned above can lead to elbow dysplasia. More precisely the different joint conditions grouped under the name of elbow dysplasia include: a ununited anconeal process (failure of union between the anconeal process and the remainder of the ulna beyond 20 weeks of age), the so-called osteochondrosis dissecans of the humeral condyle (failure of ossification of the articular cartilage covering the humeral condyle, resulting in an abnormal thickening of the articular cartilage and separation between this region and the underlying bone), and finally the fragmentation of the coronoid process (in which the ulnar coronoid process have multiple fragments or most often a single fragment). The latter two conditions often occur simultaneously.
All these conditions have a strong genetic origin, as demonstrated by the high incidence of ununited anconeal process in German shepherds and the greater occurrence of osteochondrosis dissecans and fragmentation of the coronoid process in Labrador retrievers, Golden retrievers and Newfoundlands. Other factors that can increase the risk of elbow dysplasia, and of osteochondrosis dissecans in particular, include diet and growth rates (the risk is higher in large-breed dogs overfed with high energy, protein rich diets during the juvenile growth period and given excessive supplementation with calcium) and hormonal balance (predilection of males for the development of osteochondoriss dissecans).
Regardless of the possible cause of elbow dysplasia, the age at onset of clinical signs is between 4 and 7 months (4-12 months for ununited anconeal process), while the age at diagnosis is routinely 6 to 18 months. Symptoms are common to the three conditions and include generalized forelimb muscle atrophy, swelling of the elbow joint with increased fluid and sometimes bone production, decreased range of motion with pain of the elbow joint and varying degrees of lameness that may be intermittent, exacerbated by heavy activity or most apparent after rest. In most severe cases of bilateral disease, dogs may lie in a recumbent position and be reluctant to stand or move.
Treating Elbow Dysplasia in Dogs
The treatment of elbow dysplasia can be medical or surgical, depending on the severity of the condition, the general health status of the dog, as well as the willing to cooperate and the financial availability of the owner. While surgical intervention is aimed at physically remodelling the involved joint structures through different surgical techniques, medical treatment is more conservative and is similar to that for osteoarthritis. It includes body weight restriction, exercise control and analgesic therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, phenylbutazone, carprofen and etodolac. Both approaches (medical and surgical) have been shown to provide good clinical outcomes. But, of course, clinical results are only appreciable in the long run.
Most veterinarian suggest not to breed affected dogs, their parents, siblings of affected dogs, as well as offspring of affected dogs. This advice can sound frustrating to some owners who would like to breed their pets. But it has a simple and clear rationale: elbow dysplasia, and osteochondrosis of the humeral condyle in particular, is a highly heritable disease. This means that, although the condition can be ameliorated in most cases with the proper treatment, the affected dog will always remain a carrier of the disease for the rest of its life and it can transmit the condition to its offspring. So, the only and most effective way to prevent the spread of elbow dysplasia is avoiding breeding affected individuals or their blood relatives. This is not human selection; this is only a way to follow what nature itself says: remember in fact that, in nature, most of dogs (and other animals) with birth defects cannot breed.