Hip Dysplasia is a hereditary disease that affects the hip joints of dogs. It literally means an abnormality in the development of the hip joint. Severe arthritis can develop as a result of the malformation of the hip joint and this results in pain as the disease progresses. Hip dysplasia is characterized by a looseness in the hip joint that causes abnormal wear and tear on the femoral head (the ball part of this ball and socket joint) and the  acetabulum (the socket). The wear and tear leads to malformation of the ball and socket, and can lead to arthritis. Hip dysplasia can be seen in some dogs as young as five or six months of age.

Many young dogs exhibit pain during or shortly after the growth period, often before arthritic changes appear to be present. It is not unusual for this pain to appear to disappear for several years and then to return when arthritic changes become obvious. In other dogs, signs do not develop until after the dog matures. Hip pain is generated by the abnormal arthritic bones rubbing against each other.

The onset of arthritis can be slow. In fact, sometimes the onset is so slow that you cannot recognize it. Early signs of hip pain in a dog include hopping like a rabbit with the rear legs when running, difficulty in rising from a sitting position, stiffness in the first few steps after lying down, and a reluctance to walk normal distances or play as hard or as long as normal dogs of the same age. Some young dogs might lie down on their stomachs with their legs stretched behind them. Exercise causes these signs to become more prominent. It is important to remember that dogs do not usually cry when they are in pain. Instead, they demonstrate their pain by not properly using the joint or joints that hurt. As the arthritis becomes more severe, dogs will be reluctant to play or go on long walks. Some dogs may not want to walk at all if suffering from severe arthritic pain. Most dogs with hip dysplasia will have both hips affected. Because of this, your dog may not have an obvious limp in one leg because the arthritic pain is more or less equal in both hips.

According to the OFA ("Orthopedic Foundation for Animals") some of the breeds with the highest prevalence are: Bulldog, Pug, Otterhund, Clumber Spaniel, Neapolitan Mastiff, St. Bernard, Boykin Spaniel, Sussex Spaniel, American Bulldog, Newfoundland, American Staffordshire Terrier, Bloodhound, Bullmastiff, Chesapeake Bay Retriever, Golden Retriever, Gordon Setter, Rottweiler, Chow Chow, Old English Sheepdog, Kuvasz, Norweigan Elkhound, Giant Schnauzer, German Shepherd, Bernese Mountain Dog, English Setter, Black and Tan Coonhound, Shih Tzu, Staffordshire Terrier, Welsh Corgi, Beagle, Briard, Brittany, Bouvier des flandres, Welsh Springer Spaniel, Curly Coated Retriever, Polish Lowland Sheepdog, Portugese Water Dog, English Springer Spaniel, Pudel Pointer, Irish Water Spaniel.

Keeping your dog's weight under control and providing controlled exercise are very beneficial.  Going for short walks will give you an idea of your dog's limits.  Proper exercise will maintain muscle tone and keep the joints moving and more fluid. Swimming is a superior form of exercise to achieve this goal.

When an older dog is exhibiting signs of pain associated with this condition it is often possible to help them through simple steps: healthful rest is greatly assured by providing a warm environment and a well padded bed. Additional warmth helps chronically infected joints.
Heated pet beds and mats are the perfect answer.