Elbow Dysplasia
The IEWG elbow dysplasia grading scheme
- an explanation for owners and breeders -
Leanne Fitsimmons
The expression 'Elbow Dysplasia' (ED) is
used to describe abnormal development of the elbow joint.
Regardless of the inciting cause, secondary osteoarthritic
changes are used to identify the presence of ED as well as to grade its
severity. The main primary
causes of ED are:
a
b
The flexed lateral radiograph of the elbow is required for elbow
dysplasia assessment. The image [a] depicts a normal elbow while in [b]
the anconeal process [arrow] has failed to unite to the ulna.
ED is recognized clinically in growing
dogs, usually presenting as lameness from 5-6 months of age.
Lameness is not a good indicator of elbow status, however, as
many dogs with ED are sound (ie they are subclinically affected).
Dogs with subclinical ED are capable of producing clinically
affected (lame) progeny, so it is also important to monitor ED in the
progeny of breeding stock. Many
breeds are susceptible to ED but there is a higher incidence in certain
breeds.
The most important causal factor of ED is
the genetic make-up of the dog. Other
factors, such as growth rate, diet and level of exercise may influence
the severity of ED in an individual dog, but those (environmental)
factors cannot prevent the disorder or reduce the potential of the dog
to pass the disease on to offspring.
ED has a high heritability, similar to that of Hip Dysplasia.
The scheme designed by the International
Elbow Working Group (IEWG) is based on taking radiographs of the elbow
to identify and grade signs of elbow osteoarthritis. By selecting
animals with the best elbows you can successively reduce the incidence
of ED in the progeny of your breeding stock.
The radiographic projection recommended to grade dogs for ED is a
well flexed medio-lateral view of the elbow joint. Dogs must be at least
12 months old when the radiographs are taken.
The radiographic view displays the anconeal process, which
enables any signs of ED to be numerically graded using the system
created by the IEWG. It is the thickness of any enthesophyte (new bone)
formation on the non-articular surface of the anconeal process that is
measured.
Grading System:
