Hip Dysplasia

Hip dysplasia literally means an abnormality in the development of the hip joint. It is characterized by a shallow acetabulum (the "cup" of thehip joint) and changes in the shape of the femoral head (the "ball" ofthe hip joint). These changes may occur due to excessive laxity in thehip joint. Hip dysplasia can exist with or without clinical signs. When dogs exhibit clinical signs of this problem they usually are lame on oneor both rear limbs. Severe arthritis can develop as a result of the malformation of the hip joint and this results in pain as the disease progresses. Many young dogs exhibit pain during or shortly after the growth period, oftenbefore arthritic changes appear to be present. It is not unusual for thispain to appear to disappear for several years and then to return when arthritic changes become obvious.

Factor Contributing to the Development of Hip Dysplasia

Dogs with hip dysplasia appear to be born with normal hips and then to develop the disease later. This has led to a lot of speculation as to the contributing factors which may be involved with this disease. Thisis an inherited condition, but not all dogs with the genetic tendency willdevelop clinical signs and the degree of hip dysplasia which develops doesnot always seem to correlate well with expectations based on the parent'scondition. Multiple genetic factors are involved and environmental factorsalso play a role in determining the degree of hip dysplasia. Dogs withno genetic predisposition do not develop hip dysplasia.

At present, the strongest link to contributing factors other than genetic predisposition appears to be to rapid growth and weight gain. In a recent study done in Labrador retrievers a significant reduction in the development of clinical hip dysplasia occurred in a group of puppies fed 25% less than a control group which was allowed to eat free choice. It is likely that the laxity in the hip joints is aggravated by the rapid weight gain.

Symptoms and Diganosis of Dog Hip Dysplasia

If feeding practices are altered to reduce hip dysplasia in a litter of puppies, it is probably best to use a puppy food and feed smaller quantitiesthan to switch to an adult dog food. The calcium/phosphorous to calorieratios in adult dog food are such that the puppy will usually end up withhigher than desired total calcium or phosphorous intake by eating an adultfood. This occurs because more of these foods are necessary to meet thecaloric needs of puppies, even when feeding to keep the puppy thin.

If clinical signs of hip dysplasia occur in young dogs, such as lameness, difficulty standing or walking after getting up, decreased activity ora bunny-hop gait, it is often possible to help them medically or surgically. X-ray confirmation of the presence of hip dysplasia prior to treatmentis necessary. There are two techniques currently used to detect hip dysplasia,the standard view used in Orthopedic Foundation for Animals (OFA) testingand X-rays (radiographs) utilizing a device to exaggerate joint laxitydeveloped by the University of Pennsylvania Hip Improvement Program (PennHIP).The Penn Hip radiographs appear to be a better method for judging hip dysplasiaearly in puppies, with one study showing good predictability for hip dysplasiain puppies exhibiting joint laxity at 4 months of age, based on PennHIPradiographs.

Dog Hip Dysplasia Treatment

Once a determination is made that hip dysplasia is present, a treatmen tplan is necessary. For dogs that exhibit clinical signs at less than ayear of age, aggressive treatment may help alleviate later suffering. Inthe past a surgery known as a pectineal myotomy was advocated but morerecent evidence suggests that it is an ineffective surgical procedure.However, administration of glycosaminoglycans (Adequan Rx) may help todecrease the severity of arthritis that develops later in life. Surgicalreconstruction of the hip joint (triple pelvic osteotomy) is helpful ifdone during the growth stages. For puppies with clinical signs at a youngage, this surgery should be strongly considered. It has a high successrate when done at the proper time.

Dogs that exhibit clinical signs after the growth phase require a differentapproach to treatment. It is necessary to determine if the disorder canbe managed by medical treatment enough to keep the dog comfortable. Ifso, aspirin is probably the best choice for initial medical treatment.Aspirin/codeine combinations, phenylbutazone, glycosaminoglycosans andcorticosteroids may be more beneficial or necessary for some dogs. It isimportant to use appropriate dosages and to monitor the progress of anydog on non-steroidal or steroidal anti-inflammatory medications due tothe increased risk of side effects to these medications in dogs. If medicaltreatment is insufficient then surgical repair is possible.

The best surgical treatment for hip dypslasia is total hip replacement.By removing the damaged acetabulum and femoral head and replacing themwith artificial joint components, pain is nearly eliminated. This procedureis expensive but it is very effective and should be the first choice fortreatment of severe hip dyplasia whenever possible. In some cases, thissurgery may be beyond a pet owner's financial resources. An alternativesurgery is femoral head ostectomy. In this procedure, the femoral head(ball part of the hip joint) is simply removed. This eliminates most ofthe bone to bone contact and can reduce the pain substantially. Not alldogs do well following FHO surgery and it should be considered a clear"second choice".

Hip dysplasia may not ever be eliminated by programs designed to detectit early unless some effort is made to publish the results of diagnostictests such as the OFA evaluation or PennHIP evaluations, openly. This isthe only way that breeders will be able to tell for certain what the problemshave been with hip dysplasia in a dog's ancestry.

When an older dog is exhibiting signs of pain associated with this conditionit is often possible to help them dramatically through medication and simplesteps like providing a warm bed or warm spot to rest during the day. Thereis no advantage to pain and steps should be taken to ensure that the olderdog is not in pain. Regular exercise can be very helpful and weight losscan have dramatic effects on the amount of discomfort a dog experiences.

Working with your vet to come to the best solution for your dog andyour situation will enable you and your dog to enjoy life to its fullest,despite the presence of hip dysplasia.