What is a hip and elbow score in dogs?
As a result of domestication and inbreeding, many dogs sadly suffer from defective joints. The most common conditions are hip dysplasia and elbow dysplasia.
These are developmental conditions, where the hip and/or elbow joints do not form normally, resulting in early onset arthritis and joint pain. The conditions are also genetic, meaning that they can be passed down from a sire and a dam to their offspring - but many less severely affected dogs show no symptoms until later in life, potentially after they have had many puppies.
To help breed out these problems, the Kennel Club and the British Veterinary Association set up the Hip and Elbow Scoring Schemes, and breeders are strongly advised only to breed from dogs with good scores.
So, what is hip dysplasia?
The hip joint has evolved to be a perfect ball and socket joint, allowing the femur (the upper bone of the leg) to rotate easily in the socket provided by the pelvis (hip bones), without popping out of joint. Nowadays, however, this “perfect joint” is only commonly seen in wolves and racing greyhounds - where the ability to run and keep on running is essential!
In hip dysplasia, the “socket” is too shallow for the “ball”, usually with abnormally sloping sides and a very small rim. This results in abnormal movement of the ball, leading to pain, arthritis and sometimes even dislocation of the joint. Unfortunately, except in the most severe cases, dogs can appear absolutely fine until early middle age, when progressive arthritis becomes obvious.
So how does the Hip Scoring Scheme work?
The BVA/KC Hip Scoring Scheme requires a very specific and carefully positioned X-ray of the hips under a general anaesthetic (so the dog doesn’t wriggle!). This image is then sent off to a panel of experts who will grade each of the hips on nine different criteria. These include the angle the hip makes (the Norberg Angle), how well the ball sits within the socket (“subluxation”), the shape of the socket, and the shapes of the head and neck of the femur. For each of these points, each hip is scored from 0 to 6, with 0 being perfect, and 6 being such severe damage that the joint is non-functional. At the end, they add up all the scores and send them in as a Left and a Right Hip score for the dog.
How is that useful?
The score for each hip gives an indication of how severe the dysplasia is (so, for example, a hip scoring 0-3 is usually considered normal and healthy). The specific dog can then be compared with their breed average, and only dogs with a Hip Score of less than the breed average should be bred from, to improve the breed overall and minimise the risk of Hip Dysplasia.
In the first ten years of the scheme, the average hip score of UK Labradors went down from 16.5 (1996) to 12.8 (2007)!
OK, that’s hips, what about elbow dysplasia?
Elbow dysplasia is a much more complex condition, comprising a number of different problems - but once again, it is a genetic developmental condition that seems to be becoming more common, possibly as a result of inbreeding. The most common primary disorders include osteochondrosis (OCD), fragmentation of the coronoid process (a bony spur which breaks up when loaded, FCP) and ununited anconeal process (another bony spur that fails to fuse properly to the rest of the ulnar or elbow bone, UAP).
These primary lesions appear relatively early in life - usually well before the puppy is fully grown - resulting in early onset arthritis and lameness. However, like in Hip Dysplasia, some dogs do not show clinical symptoms until much later in life.
And how are those scored?
Again, a series of carefully positioned X-rays are needed (at least two different views, and sometimes three, to highlight different parts of the joint). Each elbow is then scored 0 (normal) to 3 (significant primary lesion and/or very severe arthritis). Once again, the experts read the X-rays and send back a score for each elbow.
So, again, you only breed from dogs with better than average elbows, right?
Actually, to control Elbow Dysplasia you must be much stricter - it is recommended only to breed from dogs with a grade of 0 for both elbows.
Can anything be done to treat dysplasia once it develops?
Sadly, this is a degenerative condition that cannot be cured. However, certain primary lesions can be managed (such as using bone screws to reattach ununited bones, and removing bone chips from inside joints). The mainstay of treatment is medical, with reduction in body weight, exercise control, joint supplementation and pain relief being the main treatment options.
In severe cases, hip or elbow replacement surgery is possible and is very effective - but also very expensive!