To understand what hip dysplasia really is we must have a basic understanding of the joint that is being affected. The hip joint forms the attachment of the hind leg to the body and is a ball and socket joint. The ball portion is the head of the femur while the socket (acetabulum) is located on the pelvis. In a normal joint the ball rotates freely within the socket. To facilitate movement the bones are shaped to perfectly match each other, with the socket surrounding the ball. To strengthen the joint, the two bones are held together by a ligament. The ligament attaches the femoral head directly to the acetabulum. Also, the joint capsule, which is a very strong band of connective tissue, encircles the two bones adding further stability. The area where the bones actually touch each other is called the articular surface. It is perfectly smooth and cushioned with a layer of spongy cartilage. In the normal dog, all of these factors work together to cause the joint to function smoothly and with stability.

Hip dysplasia results from the abnormal development of the hip joint in the young dog. It may or may not be bilateral, affecting both right and left sides. It is brought about by the laxity of the muscles, connective tissue, and ligaments that should support the joint. Most dysplastic dogs are born with normal hips but due to genetic and possibly other factors, the soft tissues that surround the joint start to develop abnormally as the puppy grows. The most important part of these changes is that the bones are not held in place but actually move apart. The joint capsule and the ligament between the two bones stretch, adding further instability to the joint. As this happens, the articular surfaces of the two bones lose contact with each other. This separation of the two bones within a joint is called subluxation and this, and this alone, causes all of the resulting problems we associate with the disease.

What are the symptoms of hip dysplasia?

Dogs of all ages are subject to the symptoms of hip dysplasia and the resultant osteoarthritis. In severe cases, puppies as young as five months will begin to show pain and discomfort during and after vigorous exercise. The condition will worsen until even normal daily activities are painful. Without intervention, these dogs may be unable to walk at all by a couple years of age. In most cases, however, the symptoms do not begin to show until the middle or later years in the dog's life.

The symptoms are typical for those seen with other causes of osteoarthritis. Dogs may walk or run with an altered gait, often resisting movements that require full extension or flexion of the rear legs. Many times, they run with a 'bunny hopping' gait. They will show stiffness and pain in the rear legs after exercise or first thing in the morning. Most dogs will warm up out of the muscle stiffness with movement and exercise. Some dogs will limp and many will decrease their level of activity. As the condition progresses, the dogs will lose muscle tone and may even need assistance in getting up. Many owners attribute the changes to normal aging but after treatment is initiated, they are shocked to see much more normal and pain-free movement return.

Who gets hip dysplasia?

Hip dysplasia can be found in dogs, cats, and humans, but for this article we are concentrating only on dogs. In dogs, it is primarily a disease of large and giant breeds. The disease can occur in medium-sized breeds and rarely even in small breeds. It is primarily a disease of purebreds although it can happen in mixed breeds, particularly if it is a cross of two dogs that are prone to developing the disease. German Shepherds, Labrador Retrievers, Rottweilers, Great Danes, Golden Retrievers, and Saint Bernards appear to have a higher incidence, however, these are all very popular breeds and may be over represented because of their popularity. On the other hand, Greyhounds and Borzois have a very low incidence of the disease.

How is hip dysplasia treated medically?

Weight Management

Exercise

Warmth and good sleeping areas

Massage and physical therapy

Making daily activities less painful

Anti-inflammatory Drugs

How do we prevent hip dysplasia?

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There are many different theories on how to prevent the progression of hip dysplasia. As discussed earlier, nutrition, exercise, and body weight may all contribute to the severity of degenerative joint disease after the hip dysplasia has developed. When it comes to preventing the formation of hip dysplasia, there is only one thing that all researchers agree on, and that is selective breeding is crucial. There will be a lot of new information coming forward in the future concerning other factors that contribute to hip dysplasia, but for right now, we have to stick to what we know for sure. We know that through selectively breeding animals with good hips, we can significantly reduce the incidence of hip dysplasia. We also know that we can increase the incidence of hip dysplasia if we choose to use dysplastic animals for breeding. Breeding two animals with excellent hips does not guarantee that all of the offspring will be free of hip dysplasia, but there will be a much lower incidence than if we breed two animals with fair or poor hips. If we only bred animals with excellent hips it would not take long to make hip dysplasia a rare occurrence. If owners insisted on only purchasing an animal that had parents and grandparents with certified good or excellent hips, or if breeders only bred these excellent animals, then the majority of the problems would be eliminated. For the best results, buyers should look at three or four generations of dogs prior to theirs to ensure that there are no carriers in the bloodline. Following the newer recommendations for exercise and nutrition may help, but will never come close to controlling or eliminating the disease if stricter requirements for certified hips are not instituted or demanded.

Summary

Hip Dysplasia is a widespread condition that primarily affects large and giant breeds of dogs. There is a strong genetic link between parents that have hip dysplasia and the incidence in their offspring. There are probably other factors too that contribute toward the severity of the disease.

Osteoarthritis is the result of degeneration of the joint due to hip dysplasia. Surgical and medical treatments are targeted to prevent and treat the resulting osteoarthritis. The best way to prevent hip dysplasia is through selection of offspring whose parents and grandparents have been certified to have excellent hip conformation.

Tags: Hip Dysplasia

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