Elbow dysplasia certification scheme (US)

Dysplasia means the abnormal development of a structure, in this instance the elbow joint. The abnormal development (in young dogs) leads to degenerative or arthritic changes in the joint in mature dogs. In the elbow, problems relate to abnormal cartilage development, incorrect alignment of the bones, or unattached bone processes. Affected dogs have a genetic tendency to develop the disease but the severity of the disease can be influenced by other factors.

Elbow dysplasia is a common and often debilitating joint disease affecting many larger breed (usually pedigree) dogs. In 1990 the Orthopedic Foundation for Animals (OFA) started a database of elbow assessments. X-rays of both elbows are examined by veterinary specialists for signs of disease. In the States, OFA certification gives preliminary evaluations for dogs 5-24 months of age and final evaluation at 24 months. Breeders should be aware that, in some instances, x-ray changes do not always correlate well with clinical signs. Assessment of bony changes in the elbow result in a grade being awarded. Four grades are possible for each elbow:

• 0 = unaffected.
• 1 = mild changes.
• 2 = moderate changes.
• 3 = severe changes.

The overall grade of the dog is that of the higher graded elbow.

Ideally only dogs with grades of 0 should be used for breeding, but there is some concern that this may result in too few animals being available. It may be that different dogs have different predispositions for new bone formation and that a reduced tendency towards arthritis may also have a genetic component. Dogs with grades of 2 or 3 should not be bred. This should reduce the risk of elbow dysplasia developing in their puppies. However, it is still possible for 2 parents with very low elbow scores to produce puppies with elbow dysplasia, which is discouraging for the breeder.

The most helpful way of using the scoring information is in progeny testing. This means selecting parents which are known to have previously produced puppies with good elbows as well as having low elbow scores themselves. It is important to investigate the elbow scores of as many offspring of individual dogs as possible before selecting them for further breeding. It is also helpful to breed dogs whose grandparents’ scores were low. If it were possible to prevent any dogs who carry the gene for elbow dysplasia from producing puppies, then the disease could be eradicated.

Radiographs submitted to the OFA must follow the American Veterinary Medicine Association guidelines for positioning. The OFA recommends sedation or general anesthesia to obtain accurate positioning. This will also minimize stress for your dog associated with the radiology experience. Commonly, x-rays for hip and elbow screening are taken at the same time. The OFA requires one view of each elbow in extreme flexion. The x-rays must be permanently identified with:

• The animal’s registration number or name.
• The date on which the examination was performed.
• A right or left marker to identify which elbow is which.
• The veterinarian’s name or hospital name.

Diagnostic x-rays are submitted to the OFA together with the scoring fee and a part-completed certificate of grading. The veterinary surgeon submitting the x-ray certifies that the x-ray was taken on the date indicated and may record the dog’s microchip or tattoo number in order for the OFA to submit results to the AKC. Sire and dam information is also required.

Radiographs of animals 24 months or older are examined by 3 board-certified veterinary radiologists. The scrutineers examining the films grade them and sign the form, which is returned to the veterinary surgeon. Results are usually returned in 2 weeks from receipt of x-rays. The scored x-rays are scanned, and a digital image is kept for reference. Radiographs may be returned to owners if a written request and appropriate fee is supplied with application.

The OFA will re-evaluate animals as often as requested – but a new set of radiographs must be submitted for each evaluation. The evaluation on a given set of x-rays is final.

A small percentage of x-rays submitted to the OFA are rejected because they cannot be scored accurately. Accurate positioning is essential to give a correct score. If the elbow is twisted or not fully flexed when the x-ray is taken it may not be possible for the scrutineers to see all the features. Occasionally factors relating to the quality of the x-ray result in rejection. X-rays which are improperly exposed or processed will be too pale or too dark, resulting in loss of contrast and definition. If the features cannot be assessed, then a score cannot be given.

Incorrect identification of the patient will also result in return of the x-ray as the certificate that assigns a particular score to a specific individual cannot be signed if the scrutineer cannot guarantee that the x-ray they are looking at belongs to a particular dog.

Elbow x-rays of any breed of dog (including non-registered animals and crossbreds) may be examined; but the scheme is particularly recommended for those breeds where elbow dysplasia is common.

In certain breeds without a current problem elbow screening is being used as a preventive measure to ensure that elbow dysplasia does not creep into the breeding population.

If you are thinking of buying a pedigree puppy, find out if elbow dysplasia is likely in your chosen breed and enquire about the elbow score status of the parents before considering purchase. This can reduce the risk of elbow dysplasia developing in your puppy although it is still possible for two parents with very low scores to produce puppies with elbow dysplasia.