elbow dysplasia in dogs
|elbow dysplasia in dogs medical diagram|
Erectile dysplasia (ED) is a major problem in many dog breeds from all over the world, and although it initially arises from the puppy, it can persist to affect the dog for the rest of its life. The principal cause of ED lies in the genetic makeup of the animal. Therefore, a scheme that screens animals for elbow Anomalies will allow animals that have better elbow joints to be selected for breeding and will help to reduce the level of the problem in the canine population.
Elbow dysplasia—the disease
ED simply means ‘abnormal development of
the elbow’. The term includes a number of specific abnormalities that affect different sites within the joint. These cause problems by affecting the growth of the cartilage which forms the surface of the joint or the structures around it. These abnormalities are primary lesions, which then induce a secondary osteoarthritic process.
The most common primary lesions are:
● Fragmented or ununited medial
coronoid process (FCP)
● Osteochondritis dissecans (OCD or OD)
● Ununited anconeal process (UAP)
There are other, rarer, primary lesions that
may occur in combination with these or on their own. Primary lesions begin early during the growth of the puppy and are commonly present in both elbows to some extent.
Once the dog reaches skeletal maturity the primary lesions may stabilise. However, once abnormal development has started with a primary lesion, further secondary changes follow, in particular, abnormal wear of the joint surfaces and osteoarthritis (sometimes termed arthrosis, or degenerative joint disease—DJD). The secondary lesions cannot be reversed and remain a potential problem for the rest of the dog’s life.
The elbow is particularly vulnerable to this type of disease. The joint resembles a hinge in which the bones and cartilage forming each side of the joint have complex shapes that fit together closely. The elbow has a wide range of joint movement and normal foreleg gait is more dependent on the elbow than the other joints.
disease in that they have primary lesions or osteoarthritis in their elbows but do not appear obviously lame. Some dogs will be symmetrically lame in each foreleg, which can be very difficult to see. Fortunately, these subclinical dogs can often be identified by taking radiographs (X-ray images) of their elbows. Even though they appear to show no lameness themselves, they have a high chance of producing lame offspring if they breed.
Causes of elbow dysplasia:
ED is a multifactorial disease, which means that a number of factors can influence the occurrence of the condition. The most important factor, however, is the genetic makeup of the dog. Other factors such as growth rate, diet, and level of exercise may influence the severity of the disease in an individual dog, but they cannot prevent the disease or Reducing the likelihood of dog transmission of the disease to its dogs. However, studies show that ED has a high heritability confirming that a high the proportion of the disease is genetic.
As the individuals of each breed of dog have a proportion of their genetic makeup (genotype) in common, it is not surprising that some breeds are more vulnerable to a heritable condition than others. dogs breed medium and large so they are more likely to ED, although the condition has been found in some smaller breeds. It is a polygenic characteristic, which means that it is controlled by the combination of many gene variants. One way of visualizing this is to think of a ‘normal’ dog as carrying a few of the gene variants that can cause elbow problems. a dog with the subclinical disease will have more of these problem gene variants, and a lame animal will have a higher proportion still.
Control of elbow dysplasia:
As the genotype is the overwhelming influence in the cause of ED, the disease can be controlled by minimizing the problem of gene variants within the population. This means selecting sires and dams with the best genotype. as yet there is no laboratory test on blood or other tissue samples to enable us to select the best genotype.
Thus, dogs can be effectively examined by radiograph (x-ray) elbows finding signs of ED.
If sires and dams are only selected from animals with no or minimal ED, most of the clinical and subclinical animals can be eliminated from the breeding program, and so prevent them from passing on their defective genetic makeup to the next generation. the success of such screening depends on a high proportion of the breed participating and making the information public so that low-risk animal can be selected for breeding. There are international guidelines for screening schemes administered by the International Elbow Working Group (IEWG), which encourages a coordinated approach to the problem through regular meetings.
Initially, schemes were run by individual breed groups such as the Bernese Mountain Dog Club of Great Britain and the Guide dogs for the Blind Association, which were successful in reducing the incidence of ED.
The grading procedure Although a number of different views This ensures that most areas of the joint where abnormalities can be detected can be examined. The radiographs are examined by two scrutineers who look for primary lesions and any signs of osteoarthritis. A grade is then given for each elbow, based on the presence of primary lesions and the size and extent of the secondary lesions. The overall grade is determined by the higher of the two individual grades. Grades for each elbow are not added together as they are for the two hips in the HD Scheme.
Identification of subclinical disease and its grade in either elbow is the important factor in screening, so the grade of the worse elbow is always quoted as the overall Recorded and published in the Kennel Club Kennel Records and the Kennel Club Reproduction Records.
The grading procedure and the records are under continuous review and discussed at the annual CHS scrutineers' meeting, to enable changes in procedure to be made in light of new orthopedic research, as well as enabling the publication of information for interested parties such as dog breeders and geneticists.
The owner is liable for their veterinary surgeon’s fee for anesthetizing the dog and taking the radiographs, as well as the CHS’ fee for the grading Advice on breeding:
The overall grade is used internationally
as the basis for breeding advice. Ideally
dogs with 'normal' (grade 0) elbows should
be chosen and certainly, dogs with 2 or 3 arthroses should not be used for breeding.
As ED is a prevalent disease, especially in the breeds listed on page 3, such advice will only be effective if it is continued over a number of generations. The most difficult part of accepting such advice for many breeders The fact that some dogs never came and lame exercise freely, but nevertheless may have high grades. This is the subclinical population with the ability to pass on the problem in the breed. For long-term control of the disease, these dogs ought not to be bred from.
Treatment of clinical ED:
Dogs that have clinical ED often become lame between six and 12 months of age. initially, the lameness may be difficult to ascribe to a particular joint. However, at this age, a persisting lameness should be investigated by a veterinary surgeon, as other conditions may lead to similar signs.
Diagnosis is normally based on lameness with pain found on flexion and extension of the elbow joint as well as joint enlargement. The animal may have a short or stilted gait as both limbs are often affected.
Confirmation of the diagnosis is made by finding primary or secondary lesions on radiographs of the elbow, or by other investigations such as CT or arthroscopy. Treatment methods vary depending on the nature and severity of the problem. Conservative treatment involving weight restriction and control of exercise is always important. drugs may be used to relieve pain and inflammation and may promote repair processes within the joint.
In some dogs, surgery to remove fragments of cartilage and bone from the joint may be advised but this may not always be appropriate. In nearly all cases there will be some secondary changes which lead to further problems in the joint, and may gradually progress throughout the dog’s life and may restrict the dog’s ability to exercise.
However, most dogs will be comfortable with a fair level of exercise if treated carefully during growth between six to 18 months of age. In severe cases, it may be necessary to consider more major surgery.
Getting a dog’s elbows graded:
Owners should contact their veterinary surgeon and arrange an appointment for their dog to be radiographed (X-rayed). The radiographs must be taken under anesthesia or heavy sedation so the dog may have to be left at the veterinary practice. Elbow radiographs can be taken at the same time as those for the CHS Hip Dysplasia Scheme. When taking the dog for its radiographs owners should remember the following.
● The dog must be at least one year old, but there is no upper age limit.
● The dog must be permanently and uniquely identified by way of a microchip or tattoo.
● The dog’s KC registration certificate and
any related transfer certificates must be available so that the appropriate details can be printed on the radiographs.
● Microchip/tattoo numbers must also be printed on the radiographs.
● Radiographs of non-registered dogs may also be submitted to the ED scheme.
● The owner should sign the declaration (first part) of the certificate, to verify the details are correct and grant permission for publication of the results. Once the radiographs have been taken, the veterinary surgeon fills out the appropriate section of the certificate and submits both the radiographs and the certificate to the CHS. The results and the radiographs are normally returned to the veterinary surgeon within three weeks with the completed certificate for the owner and a copy for the veterinary surgeon.