Interpretation of hip scores
While it is impossible to correlate a hip score exactly with grades of hip dysplasia given under other schemes, an approximate interpretation for total hip scores is as follows (assuming that the two hips are similar):
0 to 4 total score: perfect or near-perfect hips
5 to 10 total score: borderline changes that are unlikely to worsen with age
11 to 20 total score: mild changes that may worsen with age, sometimes developing into osteoarthritis
21 to 50 total score: moderate to marked hip dysplasia in which osteoarthritis is already a prominent feature, or severe hip dysplasia before an arthritic change
Above 50: severe to very severe osteoarthritis secondary to hip dysplasia.
If the scores of the two hips are markedly different, the worse of the two hips should be considered to be more representative of the dog’s hip status, and doubling that single hip score will give a more realistic overall score for the purposes of selection for breeding. For example, a dog with a score of 12:3 should be considered to have a hip status similar to other dogs with a total score in the mid-20s.
Use of the hip score
When selecting a dog for breeding, the traditional advice has been that only dogs with hip scores well below the BMS should be chosen in order to apply meaningful selection pressure. Ideally, only dogs with total scores of 10 or less should be used for breeding and, more specifically, when these scores arise only from parameters 1 to 3, with a 0 score for parameters 4 to 9 (ie, no detectable osteoarthritis). This is because total hip score, Norberg angle and subluxation have the highest heritability, whereas secondary change is more likely to be influenced by age and environmental factors.