Hip and elbow dysplasia, and how to read a score

What the joint is actually doing

A hip is a ball and socket. In a dysplastic hip they do not fit: the socket is too shallow, or the ligament holding the head of the femur into it is too slack, so the joint moves in ways it was not built to.

That laxity is the disease. The body responds to a joint that will not sit still by laying down new bone at the edges and wearing the cartilage in the middle, which is osteoarthritis — and the arthritis, not the malformation, is what actually hurts.

Elbow dysplasia is the same idea in a more complicated joint. Three bones meet at the elbow and they have to grow to matching lengths; when they do not, small pieces of bone and cartilage are left loose or under pressure inside the joint. It is usually described as several distinct conditions rather than one.

Both are developmental. A puppy is not born with dysplastic hips — it is born with the genetics for them, and the joint forms badly over the first months.

Reading a score, which is not obvious

There are several schemes and they do not resemble each other.

The BVA and Kennel Club scheme, used in Britain, Ireland and Australia, scores nine features on each hip and adds them up. Each hip runs 0 to 53, so a dog scores 0 to 106 in total. LOW IS GOOD. A total of 4 is excellent; 40 is poor. It is written as two numbers — 3:4 means three on one hip, four on the other — and a lopsided pair matters, because the worse hip is the one that will hurt.

The OFA scheme in the United States gives a grade instead: Excellent, Good, Fair, Borderline, then Mild, Moderate or Severe dysplasia. Anything from Fair upward is passing.

The FCI scheme across most of Europe grades A to E, with A and B clear.

PennHIP measures laxity directly and reports a distraction index between 0 and 1, where lower is tighter. It can be done from sixteen weeks, far earlier than the others.

Elbows are usually graded 0 to 3, and 0 is clear.

The number is meaningless without the breed

This is the part that catches people out. A hip score of 12 is unremarkable in a German shepherd and poor in a border collie, because the schemes publish a median for every breed and that is what a score has to be read against.

So the question to a breeder is not what did they score, but how does that compare with the current breed median — and a good breeder will know the figure without looking it up.

Both parents matter, and so do their relatives. Dysplasia is polygenic: many genes contribute, none of them decisive, which is why it cannot be DNA-tested the way a recessive disease can. Estimated breeding values, where a scheme publishes them, combine a dog's own score with those of its relatives and are a better predictor than the score alone.

And scores are only meaningful once. A dog is scored at a minimum age — one year for BVA, two for OFA — and the result stands for life.

What an owner actually controls

Genetics load the dice and rearing rolls them, so a fair amount of this is in the owner's hands.

Keep a growing puppy lean. Overfeeding a large-breed puppy makes it grow faster than its joints can form properly, and it is the single biggest environmental factor. Large-breed puppy food exists for this reason: it is not richer, it is deliberately less so.

Avoid repeated high-impact exercise while the growth plates are open — long runs on hard ground, stairs, jumping in and out of cars, and hours of ball chasing with hard turns. Free play on soft ground is fine and good.

Stay lean for life. Weight is the most effective single treatment for an arthritic joint, and the Labrador lifetime study found lean-fed dogs developed arthritis later and less severely than their own littermates.

Swimming and controlled lead walking build the muscle that supports a loose joint without loading it.

If a dog has it

Plenty of dysplastic dogs live comfortable lives, and the severity of the X-ray does not reliably predict the severity of the pain. Some dogs with poor hips are sound for years; some with mild changes are not.

The signs are easy to read as age: reluctance to jump or climb stairs, sitting down oddly, a bunny-hopping run with both hind legs together, stiffness after resting that eases with movement, and a narrow stance behind.

Management comes first and covers most dogs — weight control, controlled exercise, physiotherapy and hydrotherapy, pain relief, and joint supplements which help modestly rather than dramatically.

Surgery exists for the dogs management does not reach. Total hip replacement is the big one and its results are genuinely good. There are also procedures aimed at young dogs before arthritis sets in, which is one reason to investigate a limping puppy early rather than waiting to see.

A dog that is stiff, slowing down or reluctant on stairs is worth a vet visit rather than an assumption about age. Arthritis is treatable and being old is not.