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Elbow Dysplasia (ED) - There are 4 main
subgroups of elbow dysplasia, which may occur alone or in combination.
Generally they are considered inherited in most breeds and the incidence may
be adversely affected by incorrect diets in some breeds. Excessive rate of
weight gain can affect the incidence of many elbow conditions, often leading
to joint incongruity (uneven rate of growth between the radius and ulna),
and OCD seen particularly in males.
1. UAP - Ununited Anconeal Process - This process is a
large triangular shaped piece of bone situated at the back of the elbow
joint. This has a separate ossification center in a handful of breeds
notably the GSD, Labrador, Great Dane, Irish Wolfhound, Newfoundlands,
Bloodhound, Basset and Afghan hounds. This process normally is fully
ossified (sealed) by 16-18 weeks of age. This condition is considered
inherited with a possible 3 different genes being involved.
Symptoms - Clinically signs are seen from as young as 5-6 months with often
an intermittent lameness, which is exaggerated by exercise. Full flexion and
extension of the elbow will elicit pain. There is often an accompanying
lateral bursitis (fluid swelling). X rays of the elbow in the flexed lateral
position will readily show whether the process has unified or not. Long
standing cases often have boney arthritic changes as well.
Treatment - Either (a) removal of the process, if done
while young, reasonable prognosis with some arthritis later, or (b) fixation
of the loose fragment by a lag screw, for reasonable prognosis in early
cases. As the anconeal process is not a weight bearing surface, results
following early surgery gives much better long term prospects than in the
FCP cases (as loss of that process affects the weight bearing surfaces of
the joint).
The majority of UAP cases in the GSD have good congruity of the head of the
radius relative to the ulna. Where there is poor congruity, ie. the radius
is too long for the ulna, osteotomy (cutting) of the ulna to allow it to
lengthen naturally is another option.
Affected dogs should not be breed from. UAP is generally considered to be
inherited as a separate condition from OCD and FCP in the GSD.
REFERENCES
Hereditary Bone and Joint Diseases in the Dog - JP Morgan et al, 2000
Veterinary Paediatrics
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