Canine Hip Dysplasia (CHD)is relatively common in dogs, and is a hereditary disease. Therefore, it is quite common in Standard Poodles, whereby hereditary plays a strong role in the breeding of specific canine lines.
CHD occurs when ligaments, muscles and tissue around the hip joint loosen, so that they no longer hold the hip joint in place. Because of this, the hip joint malforms, which often causes pain and arthritis because the bones continually rub against each other. Most poodles that have CHD have normal hips when born, but eventually end up with pain in one or both rear legs. Puppies as young as five or six months old have shown signs of CHD. However, for other dogs, it might not show up until they are somewhat older.
CHD is not a form of arthritis. Arthritis does often form in response to CHD, but it comes as a consequence of the disease, not as a form of it.
CHD can affect younger dogs or older ones. It can also affect hip joints' development in puppies, depending on when the disease begins to manifest. Much of this is due to genetics, since heredity does play a part in CHD. With some puppies, they are born with normal hips but the tissues surrounding the bone and socket itself are abnormal; the ligament between the two bones stretches, which makes the joint unstable. Thus, the bone and socket surfaces that would normally make contact with each other move apart. This slight separation is called "subluxation," which in turn causes all of the problems associated with Hip Dysplasia.
Once the hipbones lose contact with each other, the surrounding muscles work to force the bones back together but never are able to properly do so. This can often cause the femoral head to ride up into or over the rim of the socket. This makes the bones grind against each other instead of simply making smooth contact as should happen.
This means that now, abnormally shaped bone begins to grow because of the irritation caused by bones' improper contact. This turns into a vicious cycle; new bone growth causes further irritation, which in turn causes more abnormal bone growth, which in turn causes further irritation, and so on. This becomes what we call "arthritis." In general, this is very painful. Now the femoral head, which should look like a billiard ball, looks like a cauliflower head. The socket, once deep enough to enclose the femoral head, is now shallow because the rim has been ground away. The edges have become covered with bone spurs. As the hip dysplasia continues, more abnormal bone growth occurs, causing further pain and bone distortion.
When puppies have Hip Dysplasia, they will usually begin to show symptoms between 5 and 13 months of age. This can range from mild discomfort to severe pain when they use their hind legs. This usually is visible when they've been engaged in prolonged activity or when they get up or down. As they age, pain becomes increasingly severe, and the dogs will have to cut down on their activity. They will often be unable or unwilling to run or climb stairs. Because they no longer use their rear legs, muscles can atrophy and their rear legs will weaken. Some dogs will alter their gait and posture, so that no behavioral signs of Hip Dysplasia are present, even though the bone changes themselves are significant.
Some signs of Hip Dysplasia in young dogs range from small irritations to minor fractures in the bone spurs that occur around hip sockets. The fractures can occur because the pup is growing and putting more weight on them, or because of exercise. Dogs can have a sudden onset of pain or discomfort, usually after they have had significant exerciser activity. With adults, discomfort usually comes from arthritis, which in turn is caused by the deformed joints and irritation that is always present.
Hip Dysplasia is diagnosed through x-ray. In general, a dog is brought into the veterinarian with rear leg discomfort. At this time, x-rays are taken and the Canine Hip Dysplasia is diagnosed. Even dogs that show no signs of Hip Dysplasia may have it, since some dogs show no discomfort.
Hip Dysplasia is treated to help decrease or even eliminate pain, so that dogs can engage in relatively normal activities. Almost no dogs today must be put to sleep because of suffering. In general, the vast, vast majority of dogs can live comfortably even with Canine Hip Dysplasia.
The treatment of Hip Dysplasia depends upon the stage at which the disease is discovered, and includes rest. If discovered at an early stage, dogs are given medication and are confined to a cage to inhibit movement for five to seven days, to alleviate the current flareup. For older dogs, surgery may be necessary to alleviate the condition. Sometimes, dogs can be treated with pain medication and anti-inflammatory drugs for years, thus avoiding surgery.
If surgery is needed, there are three different types to use. The first one involves cutting the pectinious, which is the muscle that tries to stabilize the joint and force the two bones back together. When this muscle is cut or has a portion removed, the two bones are allowed to move apart so that the grinding of bone and socket stops. This can sometimes alleviate all pain so that further surgery is not necessary.
The second type of surgery involves removing the femoral head. Although this sounds radical, the dog's body can compensate very well, since the other muscles become stronger and will hold a leg in place without the femoral head. This allows the dog to have almost normal motion. In addition, this almost completely eliminates pain for the dog, since of course the two involved bones will no longer come in contact with each other.
The final surgical technique used in CHD is hip replacement. In this case, the joint is completely replaced with an artificial one made of high-impact plastic and still. This is a very expensive option and is almost never necessary.
Most importantly, Hip Dysplasia can be treated so that the patient in question can live a life that is free of pain, or nearly so. This can be done through medication and in more severe cases, surgery. Because Hip Dysplasia is genetic, it is common in generations of dogs from the same "family." Veterinarians can certify that a dog is or is not dysplastic by x-raying it by the time it's 24 months old. These x-rays are then sent to the Orthopedic Foundation for Animals to be graded and certified. If dogs are bred with generations certified free of dysplasia, the disease itself can be eliminated. Indeed, for those breeds that certify dogs to be dysplasia-free, the disease is decreasing. If you breed poodles, you should be x-raying your animals to certify them as dysplasia-free as well, thus helping contribute to elimination of this most painful disease.
Here's an excellent book about Canine Hip Dysplasia.