Page 79 - The Pembroke & Cardigan Welsh Corgi Worldwide Magazine
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EJCAP - Vol. 17 - Issue 2 October 2007
The OFA scoring system This allows the radiologist to assess for progressive arthritic changes that
would be expected if the dog was truly dysplastic. Most dogs (over 50%)
OFA exclusively represents the USA with this grade show no change in hip conformation over time and receive
and Canada. Dogs must be older than 2 a normal hip rating; usually a fair hip phenotype.
years of age for official scoring. A 7 point Mild CHD (Figure 5): The femoral head is partially subluxated causing an
scoring system is used, dividing the dogs incongruent and widened joint space. The acetabulum is usually shallow
in 2 groups of 3 grades each: Normal hip only partially covering the femoral head. There are usually no arthritic
conformation with excellent, good, and changes present and if the dog is young (24 to 30 months of age), a
fair score on one side, and dysplastic hip second radiograph may be submitted for re-evaluation when the dog is
conformation with mild, moderate, or older. Most dogs will remain dysplastic showing progressive DJD. Since
severe CHD on the other side. CHD is a chronic, progressive disease, the older the dog, the more accurate
the diagnosis of CHD (or lack of CHD).
Diagnostic criteria are signs of subluxation Moderate CHD: There is significant subluxation present with the femoral head
and DJD. Scoring is done independently by barely seated into a shallow acetabulum. There are secondary arthritic changes
3 trained radiologists from a consulting pool usually along the femoral neck and head (remodelling), acetabular osteophytes
of certified veterinary radiologists. The score and various degrees of trabecular bone pattern changes called sclerosis.
reflects their pooled consensus which is Severe CHD (Figure 6): Radiographic evidence of marked dysplasia. There is
reported back to the owner. Excellent, good signifi cant subluxation with the femoral head partly or completely out of a
and fair hip grades are considered to be shallow acetabulum. There are massive secondary arthritic bone changes
within normal limits. Such animals receive along the femoral neck and head, acetabular rim changes and large
an OFA number, and their results are placed amounts of abnormal bone pattern changes.
in the public domain and are available on
the OFA’s website. For dysplastic dogs The BVA/KC scoring mode
(borderline, mild, moderate and severely BVA/KC is used in Britain, Ireland, and Australia/New Zealand to score each hip
dysplastic) a radiographic report is given to joint based on the severity of changes of 9 specifi c morphological radiographic
the owner. Unless the owner has chosen the criteria examined. They are NA, subluxation (2 criteria), shape and depth of
open database, dysplastic hip grades are not acetabulum (5 criteria), as well as shape and signs of DJD at the femoral head
in the public domain. and neck (2 criteria). Each criterion is scored from 0 (ideal) to 6 (worst). Final
hip score is offered as the sum between 0 and 53 for each hip joint and as
the sum of both hips (0-106) (Table 2). Scoring is done by 3 panellists out of a
Some cases may be scored as borderline. group of certifi ed radiologists or small animal surgeons jointly.
There is no consensus between the
radiologists to place the hip into a given What are the pros and cons of each scheme?
category of normal or dysplastic. There is
usually more incongruence present, but no FCI accepts scores made by anyone considering himself expert in the
arthritic changes that would definitively radiological evaluation of canine hip conformation. The individual breed club
selects a veterinarian of its preference as scrutineer. Training and competence
diagnose the hip joint being dysplastic. of the scrutineers vary enormously from self trained practicioners and in some
There also may be a normal anatomic occasions even lay persons to highly skilled certifi ed veterinary radiologists or
variant for that individual breed. To increase small animal surgeons. Quality of scoring varies accordingly. Comparison of
the accuracy of a correct diagnosis, it is final grades between coutries may become extremely diffi cult or simply not be
recommended to repeat the radiographs at a possible. Furthermore one single breed within a country may have broken up
later date (usually 6 months). This allows the into different breed clubs and these clubs may work with different scrutineers
hampering comparison of the results even within a country. Estimated
radiologist to assess for progressive arthritic heritability of an average of 30% (reaching 50% in well designed studies) is
changes that would be expected if the dog somewhat lower than that of BVA/KC, but still offers ample information for
was truly dysplastic. Most dogs with this selection of breeding stock against CHD.
grade show no change in hip conformation
over time and receive a normal hip rating. The website of FCI (www.fci.org) does not provide much help for the breeder,
since FCI considers its most important duties to keep track of the standards
for each of the 338 recognized breeds, to provide internationally accepted
pedigree form (but does not issue any pedigree), to train judges and to collect
Scoring radiographs for canine Hip Dysplasia - The big
three organisations in the world: Figs. 1-6: Schematic and list the results of dogs in shows and trials. Good information on the
drawings of the 6 OFA gradings. procedure can be found on th website of the Italian fondazione salute animale
(FSA) (www.fondazionesaluteanimale.it/CENTRALE/index.html)
Figs. 1-6: Schematic drawings of the 6 OFA gradings.
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