What is hip dysplasia?
Hip dysplasia is one of the most common bone and joint diseases in dogs. It literally means 'abnormally developed hips'. Affected dogs have hips that do not fit perfectly into their ball and socket joint, leading to problems with how the hip moves. Long-term, this can cause arthritis and pain.
Dogs with dysplastic hips will have increased flexibility in their hip joints, causing ‘joint laxity’ and ‘subluxation’. This means the top of the femur bone in the leg, which should normally fit snugly into the ‘socket’ of the ‘ball and socket joint’ that is the hip, sits loosely and only partially in the socket. This causes abnormally intense pressure to be placed on the joint, and the cartilage covering the top of the femur to get damaged and rubbed away. Damage to the joint cartilage and abnormal wear of the bone on the femur and pelvis, causes painful osteoarthritis which worsens over time. This can cause lameness and limping, pain getting up and down stairs or in and out of bed, and reduced ability to exercise. Hip dysplasia differs in severity between different individuals. Some affected dogs will develop advanced disease within the first year of life, whereas others will develop a mild version of the disease that does not cause noticeable arthritis until they are an older dog. There is no cure for hip dysplasia and osteoarthritis; they must be managed with pain relief and anti-inflammatories if they become severe enough. Hip dysplasia is common in many breeds of dog. It is important that breeders of commonly affected breeds screen their breeding dogs for hip dysplasia and only breed from those dogs with better-than-average hips. This will minimise the chance their puppies will have severe hip dysplasia and improve the overall quality of hips in the breed. Hip dysplasia is a complex disease and there are different factors that influence its development. No breeder can ever guarantee that a puppy will not develop hip dysplasia, but there are things they can do to limit their chances.
How can a breeder test for it?
Hip dysplasia is a complex disease with many different factors contributing to how it manifests. We know there is a large genetic component to hip dysplasia, but there are several different genes likely to be involved and there is no simple genetic test that can screen for it. The test for hip dysplasia is an xray on the breeding parents. The xray will show if there is any sign of joint laxity, subluxation or arthritic changes in the hip joints. If there is evidence the breeding dog might have hip dysplasia or looser than average hips, this dog should not be selected to breed.
Why is it important to test for it?
Some breeds, such as the British Bulldog, are very predisposed to hip dysplasia and well over 50% of dogs will have the disease. Other breeds, such as the German Shepherd, have a lower percentage of dogs affected but a higher proportion of these seem to develop very painful osteoarthritis. In any breed known to be predisposed to this disease, breeders should xray their breeding adults in order to decrease the risk that their puppies will be badly affected. We do not know exactly how hip dysplasia is inherited so it is best to avoid breeding from dogs showing significant hip dysplasia altogether. In breeds where the disease is very common, it may limit the genetic diversity of the gene pool too much if we stopped breeding from affected dogs altogether. In these breeds it is best practice to only breed from dogs who have better-than-average hips for their breed. These breeders should specifically seek out a testing methodology that provides their dogs with a ‘hip score’ so they can objectively compare their dogs against published breed averages. By doing this, breeders can help to gradually improve hip genetics in their breed.
How do I interpret the hip results from my puppy’s parents?
Your breeder will have chosen one of three methods to evaluate their dog’s hips:
PennHip Scoring
This is a widely used hip scoring method that measures ‘passive hip laxity’. The xray will be taken by a vet trained in the PennHip method, and a ‘distraction index’ (DI) will be calculated to indicate how tight the dog’s hips are. The DI is a score between 0 and 1. A score of 0-0.3 = tight hips (less likely to get hip dysplasia). The closer to the score is to 1 the looser (more likely to get hip dysplasia) they are. A score of >0.7 = loose hips (at high risk for developing hip dysplasia). The average score for many breeds is around 0.5.
2. Extended hip xray submitted to a hip scoring scheme eg. CHEDS, OFA or FCI
This is another method of positioning for a hip xray. Each scheme will have their own grading system to classify the hip score. The xrays will be graded by specialist veterinarians endorsed by each scheme.
The CHED scheme (Canine Hip and Elbows Dysplasia Scheme) is the scheme endorsed by the Australian National Kennel Council (ANKC). Their hip scores are a number between 0-106, with 0 being perfect hips and 106 being the worst hips possible. Scores of <10 are desirable for breeding dogs, although cut-offs will differ from breed to breed.
The OFA (Orthopedic Foundation for Animals) is a popular hip scoring method where the hips are classified as ‘Excellent’, ‘Good’, ‘Fair’, ‘Borderline’, ‘Mild’, ‘Moderate’, or ‘Severe’ based on the xray. Breeding is not recommended from dogs with mild, moderate or severe hips.
The FCI (Federation Cynologique Internationale) is a popular European scoring scheme that provides the dog with an internationally recognised hip score from A-E.
3. Xray evaluated by their general practitioner vet
If a breeder does not have access to a specialist who can evaluate their xray as part of a scheme, they might ask their local vet to take and evaluate the xray. Whilst this is a more subjective test and does not give a score that can be compared with other dogs, it can be used to rule out moderate or severe dysplasia to avoid breeding from these dogs.
Whilst RightPaw encourages breeders to pursue hip scoring, we do not individually evaluate each dog’s results. If a breeder lists hip dysplasia in the health tests on their profile, then we have confirmed they have results for the parents of their current litter. Your breeder should be able to forward you a copy of these results if you wish to make your own assessment of them.
My new puppy is a breed that commonly gets hip dysplasia. What should I do to minimise the chance they get it?
Hip dysplasia is a multifactorial disease, meaning that there are polygenetic and lifestyle factors that influence your dog’s likelihood of developing it. Even if your breed is predisposed to developing the condition there are several things you can do to try to reduce your individual dog’s chance of developing severe disease:
Weight control! This is the number one most important factor for reducing the development of and managing the pain of osteoarthritis. The more weight your dog is carrying the more excessive force is placed on their joints and the more arthritic change will develop. Keep your dog slim throughout their life to minimise this risk factor.
Nutraceuticals, antioxidants and supplements. There is lots of research going into these products currently and there are many of them available for the prevention and management of osteoarthritis. These compounds work by reducing inflammation and promoting healthy cartilage.
Joint-friendly diets enriched with omega-3 fatty acids and eicosapentaenoic acid (EPA).
Gentle regular exercise. Keeping those joints moving and functioning well is important to promoting joint health, but the exercise should not be excessive or high-impact. Gentle walking and swimming are ideal forms of exercise for promoting healthy joints.
Acupuncture and cartilage protector injections. These can be used as preventative and management tools for osteoarthritis. Speak to your vet about where you could have these done.
