What Causes Hip Dysplasia in Dogs and How are Hip Scores Determined?

Vet checking a dog's hips

What causes hip dysplasia in dogs? How can you ensure the breeder has conducted the necessary testing and how you should interpret those results?

Hip dysplasia, especially in larger breeds, is a potential condition you want to rule out  in your prospective puppy.

What is Hip Dysplasia In Dogs?

Hip dysplasia is where the ball joint of a dogs femur or thigh bone does not sit snugly in the dog’s hip socket.

This can lead to pain and discomfort leading in some cases to lameness in one or both hind legs.

Arthritis can develop and is likely to get worse as the dog ages.

In the x-ray pictures below the example of the left is from a dog with ‘healthy hips’. You can see that the femur sits nicely in the hip socket.

The x-ray on the right shows a dog with hip dysplasia. You can clearly see that the femur does not sit snugly in the hip joint.

Xray of healthy dog hips
X-Ray of a Healthy Dog
Xray of dog with hip dysplasia
X-Ray of Dog with Hip Dysplasia

What Causes Hip Dysplasia In Dogs?

Most cases are hereditary with the condition being passed down through the generations. This is why the testing of parents in larger breeds is important to determine the likelihood of their offspring developing the condition.

Research has suggested that the circumstances of a dogs upbringing  can also have a bearing on its susceptibility to hip dysplasia. 

In a study on Golden Retrievers it was found that the twice as many dogs who were neutered before full maturity exhibited hip dysplasia compared to those that were intact at full maturity. There was also a statistical difference between early and later neutered dogs. Bitches showed no significant difference.

[Source: PLOS – Neutering Dogs: Effects on Disorders and Cancers in Golden Retrievers]

It is also thought that being overweight, excessive exercise in young dogs or injury in the formative years can also increase the likelihood of hip dysplasia.

Symptoms are usually observed before 18 months of age and, although it can be seen in smaller breeds, hip dysplasia is normally associated with large and very large breeds.

So from a Poodle Mix perspective you should be especially interested in the ‘hip health’ of your prospective puppy’s parents if they are a large breed such as standard Poodles, Labradors, Golden Retrievers, Bernese Mountain dogs etc. or for those Poodle Mix Cross Breeds so called Double Doodles (e.g. Goldendoodle x Goldendoodle or Labradoodle x Labradoodle breeding)

Testing of Hip Dysplasia In Dogs

You have decided you want a larger poodle mix, what should you look for from the breeder to ensure the chances of your puppy developing hip dysplasia are at a minimum?

If you are dealing with a good breeder then they should have tested the parentage to assess their hip scores and determine whether they are low enough to suggest there would be a low risk of their progeny developing the condition.

In the UK the score is determined by two specialists examining the hip x-rays of tested dogs by measuring nine aspects  of each hip joint. 

The test will produce a score for each hip, this will be a number from 0 to 53 for each hip which is then added together to give an overall assessment. A score of 0 means that the hip is perfect with 53 being the worst score possible.

The score is often shown as a two digit representation such as 6/5 or 6:5. This indicates that one hip has a score of 6 with the other having a core of 6 giving an overall score of 11.

Average scores for breeds have been established over the last 15 years. Popular breeds have more statistically robust mean values due to the number of dogs tested where some breeds have had low numbers tested so are not so statistically significant.

Popular breeds such as the Labrador, Golden Retrievers and Bernese Mountain dogs have mean values of 12.1 (51558), 15.0 (14230), 12.9 (2251) respectively. The numbers in brackets detail the number of tests conducted in the 15 years up to 2015.

A full list of breed scores (2015) is compiled by the Kennel Club and can be referenced here.

[Source: Kennel Club – Hip Dysplasia and Breeding Advice]

What to look for in Hip Dysplasia Scores

What scores is a good score then. Simplistically the lower the better, ideally you should be looking for the score to be lower than the average if possible. So in terms of a Labrador for example a score of 2:3 or 5 in total would be good as it is significantly lower then the average of 12.1 and indicates that the chances of your puppy developing hip dysplasia through its parents genes are low.

It should be noted that in other countries the hip score or assessment will not be represented in the same manner. Some assessments may give less detailed ratings and be expressed in terms such as a low, medium or high rating.

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