Hip dysplasia is the most common problem that affects the hip joint of dogs. It is the result of abnormal formation and progressive loosening of the joint. The hip joint is formed by the femur inserting into a socket in the pelvis. All breeds are susceptible to this condition although hip dysplasia is most prevalent in large breeds.

Hip dysplasia is an inherited trait. The exact mechanism of genetic expression is still unknown. It is under the influence of multiple genes. Environment, to a lesser degree than genetics, can also influence the development of hip dysplasia. Primarily, feeding practices have been shown to have an effect for some dogs. Dogs that are fed 25% less food than those eating as much as they want (free choice) are less likely to develop dysplastic hips. For this reason puppies should be fed all they want to eat in a ten minute period twice a day instead of free choice.

Hip dysplasia occurs when there is disparity between the growth of bone and muscle. Dysplasia results when the muscle mass is not strong enough to hold the bones of the joint together. The most critical time of development is from just a few weeks of age to six months. Once the joint begins to separate, degenerative changes occur in the cartilage and bone of the joint due to abnormal stresses. The degenerative changes are the cause of the pain and clinical signs associated with this disease. These clinical signs may come and go without any apparent reason but are often noticed after exercise then rest.

Signs of hip dysplasia may begin at a few months of age up to old age, but most cases are diagnosed between 6 and 24 months of age. Owners may notice the dog is having difficulty rising, limping, or running with both hind legs together (bunny hopping). There may be pain or increased movement of the bones in the joint on physical exam. The clinical signs are important indicators of the disease, although the only way to definitely diagnose hip dysplasia is with an x-ray examination. The changes seen on an x-ray may not be apparent until two years of age. For this reason dogs must be at least two years old to be certified free of dysplasia by the Orthopedic Foundation for Animals. For dogs at risk for this disease it is recommended that breeding animals are certified in this manner.

There are a number of both medical and surgical treatment options available ranging from rest and aspirin to total hip replacements. Each case is treated individually according to its severity, the age of the dog, and the desires of the owners. The ultimate goal is to reduce the incidence of this disease by controlled breeding. This is accomplished by breeding only normal dogs and using a stud with a history of producing normal progeny. Hip dysplasia is a devastating and crippling disease which deserves our efforts to reduce its frequency.