Health testing--What is elbow dysplasia?

Well, have you recovered from learning about Hip dysplasia? Elbow dysplasia should be slightly easier to discuss since currently we only use one method for evaluation--OFA. The following information is condensed from the OFA site. For further information, please refer to http://www.offa.org/ .

Elbow dysplasia is a general term used to identify an inherited polygenic disease in the elbow of dogs. Three specific etiologies make up this disease and they can occur independently or in conjunction with one another. These etiologies include:

(1) Pathology involving the medial coronoid of the ulna (FCP)

(2) Osteochondritis of the medial humeral condyle in the elbow joint (OCD)

(3) Ununited anconeal process (UAP)

Studies have shown the inherited polygenic traits causing these etiologies are independent of one another. The most common Clinical sign an owner may see in their dog is lameness which may remain subtle for long periods of time. No one can predict at what age lameness will occur in a dog due to a large number of genetic and environmental factors such as degree of severity of changes, rate of weight gain, amount of exercise, etc.

Since Subtle changes may occur over time, it often taks a vet exam to note any excessive inward deviation of the paw which raises the outside of the paw so that it receives less weight and distributes more mechanical weight on the outside (lateral) aspect of the elbow joint away from the lesions located on the inside of the joint and affects the appearence of lameness in the gait. Range of motion in the elbow is also decreased. One may notice a stiffness in the front legs as the dog gets up and down.

What Does Elbow Dysplasia look like?

The most sensitive view used to diagnose secondary degenerative changes in the elbow joint is an extreme flexed medio-lateral view of the elbow (Figure 1) which is required by the OFA and recommended by the International Elbow Working Group. The veterinary radiologists are most interested in the appearance of the anconeal process of the ulna.

When there is instability of the elbow joint due to elbow dysplasia, one of the most sensitive radiographic findings is new bone proliferation (osteophytes) on the anconeal process of the ulna (Figure 2) associated with secondary developmental degenerative joint disease.

Sometimes the associated Bone proliferation can be very subtle to visualize in some dogs and may require the use of a special light source (hot light) rather than a traditional view box to diagnose it. Other arthritic findings such as sclerosis in the area of the trochlear notch of the ulna and bone spurs at joint edges are also reported and wwould be mostlikely seen in advanced cases.

If fragmentation of the medial coronoid only involves the cartilage, it may not be seen radiographically but occasionally if the bone is also fragmented, it can be visualized as a separate calcific opacity superimposed over the radius (Figures 3 and 4).

Evaluating and Grading the Elbow

For elbow evaluations, there are no grades for a radiographically normal elbow. Normal is normal. The only grades involved are for abnormal elbows with radiographic changes associated with secondary degenerative joint disease.

Like the hip certification, the OFA will not certify a normal elbow until the dog is 2 years of age. The OFA also accepts preliminary elbow radiographs. To date, there are no long term studies for preliminary elbow examinations like there are for hips, however, preliminary screening for elbows along with hips can also provide valuable information to the breeder.

Grade I Elbow Dysplasia-Minimal bone change along anconeal process of ulna (less than 3mm).

Grade II Elbow Dysplasia-Additional bone proliferation along anconeal process (3-5 mm) and subchondral bone changes (trochlear notch sclerosis).

Grade III Elbow Dysplasia- Well developed degenerative joint disease with bone proliferation along anconeal process being greater than than 5 mm.

Some breeders believe that Grade I elbows are within the “normal” range, much like Fair hips are considered to be within the normal range. What is the OFA’s position on this?

The OFA’s distinction between normal and abnormal elbows is actually more clearly defined than are the differences between fair and borderline hips. Elbows are diagnosed as dysplastic when evidence of Degenerative Joint Disease (DJD) is present as evidenced by osteophytes or sclerosis. Thus, DJD is a "symptom" of ED.

It is not a gradual continuum from normal to abnormal, in which minor differences might be interpreted as normal by one reader and abnormal by another. The degree of DJD present is the determining factor in the grade of dysplasia.

The term “degenerative joint disease” is often misunderstood and misinterpreted. “Degenerative” is defined as some distinct change from a normal state to a diseased state. It does not imply a continuing process in which the disease will progress and worsen continuously over time, and it is incorrect to assume that a dog with Grade I ED will eventually develop Grade II or III ED.

It is also important to understand that DJD is a finding which aids in the diagnosis of elbow dysplasia, but the DJD itself is the secondary result of one or more of three distinct "causes" of ED(listed above) that make up the generalized description of elbow dysplasia.

My dog has never limped. How can it have elbow dysplasia?

The radiographic evidence of ED, the presence of secondary DJD, and the clinical presentation do not correlate directly. Grondalen did a study and reported on a population of 207 Rottweilers affected with ED and 141 were not lame. Yet 68% of the non-lame dogs had DJD of the elbow.

Another ED study by Read reported on serial radiographic (x-rays) and physical examination of 55 Rottweilers at 6 and 12 months of age. At 6 months of age the majority of lame dogs did not have radiographic evidence of ED; however, by 12 months of age the radiographic changes were apparent. But the majority of dogs remained sound.

Like hip dysplasia, many dogs affected with Grade I ED do not exhibit lameness; and like hip dysplasia, breeders cannot depend on using clinical signs to diagnose the disease. Dogs with minimal pathology involving the medial coronoid process may not always present clinical lameness, as the DJD and fibrosis of soft tissues may actually help to stabilize the joint. It is very likely that using lameness as a guideline to accept the diagnosis of ED would permit an increased incidence of disease genes to proliferate in the breeding population.

My Vet says my dog has Elbow dysplasia, but it doesn' t limp. Can I breed it?

The OFA acknowledges that breeding decisions are personal and that health testing is a tool to be used by the breeder. So, they will not tell a breeder NOT to breed a dog. . OFA and MCOA (Mastiff Club of America) do not regulate breeding practices or impose testing requirements.

The OFA’s main function still remains to provide breeders with the tools and information to make more informed breeding decisions and their purpose remains to assist breeders in reducing the incidence of genetic disease including elbow dysplasia.

The OFA strongly recommends that dogs from the "at risk breeds "being considered for a breeding program, as well as their siblings, be radiographed to determine their elbow status. This information should be an important and carefully considered part of breeding decisions.

Can a dog only have Elbow Dysplasia in one elbow?

Since an injury can lead to the changes associated with ED , sometimes you will note that an injury may cause a dog to get a "fail"in one elbow. As a breeder--this then becomes a judgement call. IMO-if it was "genetic" both elbows would have and demonstrate changes. IF a dog has no other "joint" issues (i.e the other elbow and both hips are normal) and there are no related dogs (1/2 and full siblings, parents, and grandparents) with ED---I do not consider ED in one elbow as genetic.

Breeding a dog that has ED in one elbow is a judgement call. I have used a stud dog that has ED in one elbow--but he had been bred before and had never produced ED and he also has a Vet documented injury to that elbow. My Vidalia injuried her right elbow at age 22 months--twisting and damaging the joint in a fall down some icy steps.

When I did her pernament OFAs, her right elbow did not pass. I had pre-limned her at 10-12 months and knew her elbows were normal; I had witnessed her injury--so I bred her. None of her puppies have ever developed ED--nor have any on her grandpuppies. I also knew that none of her 1/2 and full siblings had ED--and her grand parents were clear. By knowing all the doigs behind in her pedigree, I was confident that her failed elbow was due to the previous injury and was not genetic.

Conclusion

It is only through a proper exam (x-ray) and evaluation can elbows be "cleared" of elbow dysplasia and be determined to be "normal". If siblings (full or 1/2 brother and sisters) have bilateral ED, one could predict that a littermate or sibling would have an increased risk of having or passing on ED.

It is essential to any breeder to fully know the health issues within the lines of the dogs they breed. Health testing is not a 100% guarrentee, but it can certainly stack the odds in your favor to produce a sound healthy puppy.

Please feel free to foward any questions or comments to me at kiokeemastiffs@embarqmail.com. Thank you. Catie Arney