Hip Dysplasia

Definition The term "hip dysplasia" refers to poorly formed hip joints, comprised of the head of the femur (thigh bone) and the acetabular cup (hip socket). It is thought to be the result of many factors including breed tendencies, genes, diet, growth rate and exercise. Over time, the "loose" joint results in bony degenerative changes or arthritis of the hips with resulting lameness, stiffness and pain. Predisposed Breeds While there are many dog breeds that are affected, four breeds- German Shepherds, Golden Retrievers, Labrador Retrievers and Rottweilers- both purebreds and mixes, represent 50% of the population of dogs with hip dysplasia. Because there is evidence that this is an inherited disease, it is particularly important in these breeds, but also in all dogs, to evaluate for hip dysplasia PRIOR to breeding. While a dog with no signs of hip dysplasia makes it less likely to be carrying the genes for this, it doesn't completely rule out the potential of its transmission. Prevention Through Diet and Exercise Diet A diet high in calcium and protein predisposes a pet to development of hip dysplasia. For this reason, addition of calcium supplements and/or feeding high protein diets is discouraged. Feeding a well-balanced, puppy diet for a young, growing dog is recommended. For the large breed dogs, some food companies have developed "large breed puppy" diets to allow for slower skeletal growth and in some studies, this has been shown to decrease the chance for hip dysplasia. Studies have been done to show that feeding excessive amounts of puppy food stimulates faster skeletal growth, and this predisposes to hip dysplasia. For this reason, feeding proper amounts only is encouraged (note that the guidelines for food amounts to be fed printed on pet food packages tend to be on the high side). Monitoring your puppy's weight is important, and this can be done during recheck visits during his growth. Giving lots of extra treats and feeding "people food" is discouraged since obesity is another predisposing factor to hip dysplasia. Exercise Throughout your puppy's growth, walking and low levels of running are acceptable, but excessive and hard running can be another contributing factor of hip dysplasia and other bony problems. Signs of hip dysplasia These include painful hindquarters, reluctance to jump up and down and going up and down stairs, stiffness upon rising, especially after exercise and "bunny hopping" when running. These signs can occur at any age, but sometimes only manifest when the dog is older and has not only laxity of the hips but also arthritis. The condition is worsened when the animal is overweight. Diagnosis Radiographs These can be taken at any age if the animal is showing signs. However, radiographs taken for certification with the Orthopedic Foundation of Animals (OFA) are taken at 2 years of age since this is considered to be the time of skeletal maturity. Since good positioning is crucial to evaluate the hips, radiographs are taken with the animal lightly sedated. Radiographs are usually taken with the animal positioned on its back, although a new technique involves placing them chest down (dorsolateral subluxation (DLS) method). The purpose of the radiographs is to evaluate the percentage of the head of the thighbone covered by the hip socket. The higher the percentage, the less likely the dog will develop dysplasia. Radiographs are sent to OFA which grades the hips as excellent, good, fair or poor. Hips joints with signs of dysplasia are classified as having mild, moderate or severe disease. It is recommended not to breed dogs with signs of hip dysplasia. Note that there are special forms to be filled out for OFA certification and if you are interested in having OFA certification done on your dog, please discuss this with your veterinarian. PennHip technique This is another technique that can be used to evaluate hip dysplasia. It gives an index that indicates a dog's laxity in its hips and thus, its susceptibility to hip dysplasia. This technique can be done as early as 4-6 months of age. However, it requires special equipment and training of the veterinarian and thus is available only at a few hospitals in the area. Surgical Correction There are 3 surgical techniques exist to correct hip dysplasia. They are usually used to correct moderate and severe cases. Total hip replacement (THR) This procedure involves the implantation of a hip prosthesis with a new "ball and socket". Triple pelvic osteotomy (TPO) This procedure involves cutting the pelvis and realigning it to give better hip confirmation. Juvenile Pubic Symphysidesis (JPS) This technique is relatively new and involves stopping pelvic development in the pubis to allow for a different pelvic angle to develop. This allows for an improved and tighter hip joint. However, this procedure must be done while the pelvis is still growing and the dog is young, between 14-20 weeks of age. The total hip replacement and triple pelvic osteotomy techniques can be done on young or older dogs. These surgeries, done by board-certified surgeons, are costly and can be done at a few hospitals in the Bay Area. Medical management These tend to be long-term treatments designated to help the dog cope with the disease rather than cure the condition. Mild cases of hip dysplasia can often be managed medically. Weight loss This is important in individuals who are overweight since obesity further stresses the joints and makes the condition more painful. Non-steroidal anti-inflammatory drugs (NSAIDS) These drugs are used to decrease joint inflammation. These include over-the-counter medications such as ascriptin or buffered aspirin. Note that acetaminophen (Tylenol) and ibuprofen (Advil and Motrin) and naproxen (Aleve) should not be given to dogs since they can cause ulcers and can be toxic to other organs. However, long-term aspirin use or even occasional in some dogs can cause ulcers. Veterinary prescription drugs such as carprofen (Rimadyl), etodolac (Etogesic), melaxicam (Metacam) and deracoxib (Deramaxx) are designed for use in dogs and tend to cause less stomach upset and are safer for long term use. Depending on the severity of the hip disease, it may be an on-going treatment or sometimes, may be given as needed. Glucosamines This refers to a broad class of products, called nutraceuticals and are available as both over-the-counter human derivatives and veterinary drugs. While most dogs show improvement when started on these, they can vary in their response. It usually takes 6-8 weeks for the medications to take full effect. They work by increasing the amount and quality of joint fluid. Glycoflex, Vetridisc and Cosequin are oral veterinary forms of these medications and Adequan is an injectable form. Over-the-counter brands include: human drugs Pain-free, Move-free, Cosequin, shark cartilage and Trader Joe's brand for pets. To be maximally effective, they should contain glucosamine and chondroitin. Steroids In general, these are not recommended for long term treatment because of side-effects, both systemic (effects on liver, kidneys, pancreas, adrenal glands) and local (while decreasing inflammation, it can further damage the cartilage). If you have questions regarding this disease or its treatment, don't hesitate to contact your veterinarian. The above is general veterinary information. Do not begin any course of treatment without consulting your regular veterinarian. All animals should be examined at least once every 12 months.