COMPARISON OF VARIOUS ASSESSMENT SCHEMES FOR HIP DYSPLASIA

The BVA does not issue grades and neither does it allocate subjective descriptions of the degree of HD (e.g. ‘mild’, ‘severe’) to specific scores. The BVA Scheme instead creates a score based on individual parameters in each hip, including both those which describe subluxation (i.e. reflecting laxity in the soft tissues) and those which describe secondary, degenerative change (i.e. osteoarthrosis, OA). Two dogs may receive the same score for different reasons: one because of severe subluxation without evidence (at the time of radiography) of OA, and the other because of much milder subluxation but in the presence of OA. Both of these are clear evidence of significant HD, albeit in different manifestations. The BVA’s recommendation to breed only from dogs with scores below the breed median or well below the breed mean takes into account both the fact that the same score can arise from different causes and also that anatomical variations between breeds exist. other HD schemes link the two processes of underlying laxity and secondary OA and their subjective descriptions do not easily allow categorisation of dogs with predominantly subluxation or predominantly OA. It is therefore impossible to give precise numerical equivalents to the descriptive grades of other schemes which will apply to every case. Should a dog be considered for importation into the UK for breeding the BVA’s advice is for its hip radiograph to be submitted for scoring, to permit meaningful comparison with other dogs of the same breed.

A further complication is the use of highly subjective terminology such as ‘fair’, ‘mild’, ‘moderate’ etc. in other schemes. In English many vets (and doctors) would use an extra term ‘marked’ between categories of ‘moderate’ and ‘severe’ when describing any type of abnormal medical finding. Therefore the BVA scores given in the table reflect the description of the hip given in OFA’s explanatory text, rather than our opinion of the degree of HD present. For example, our scores of 9-18 per hip fit with OFA’s description of ‘mild HD’ whereas we would consider dogs with scores at the higher end of this range to be much more than ‘mildly affected’ by the disease.

Note:
a) Final grading is based on the appearance of the worse of the two hips for FCI (Europe), Germany, Switzerland and OFA (USA).
b) UK (BVA) scores are therefore shown for ONE joint only; the higher of a dog’s two individual hip scores should be considered when making comparisons with other schemes, not the dog’s total score.

The table below gives an approximate correlation between different schemes.