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General Information
THIS WILL BE WHERE THERE ARE TOPICS OF INFORMATION ABOUT SOME OF THE PROBLEMS THAT MAY FACE DOG BREEDS [ NOT NECESSARILY SPECIFIC TO G.S.D. ] ooOOoo THIS FOLLOWING INFORMATION IS FROM MY OWN SEARCHES AND RESEARCH, PLEASE ALWAYS CONSULT YOUR OWN VETERINARIAN ooOOoo Simply stated means an "abnormal formation" of the hip joint.
Think of the condition first as a looseness in a joint that should be snug -
then most of the problems attendant to hip dysplasia are a result of this "looseness".
The normal anatomy of the hip joint is a classic Ball and Socket joint. The head of the femur (the "Ball") is supposed to match the acetabulum (the "Socket"). A good hip joint has a neat, snug fit between the ball and socket - that is, the head of the femur should not be slipping and slopping around somewhere in the neighbourhood of the acetabulum! There are infinite variations of dysplasia - ranging from only very slight changes from normal to complete dislocation. Consequently, no two dogs will be affected by CHD exactly alike. HOW IS CHD ACQUIRED? This is one disorder that has been proven, positively, to have a genetic basis. How much of a genetic origin in each case can vary from 25% to 85%.
A condition that is completely determined by genetics, for example gender, has a Heritibility Factor of 1.
A condition totally unaffected by genetics, for example a broken leg, has a Heritibility Factor of 0.
Studies have shown that CHD's Heritibility factor ranges from .25 to .85; this is a significant genetic contribution. So the Heritibility Factor for a given dog is the result of a combination of the Heritibility Factors from each parent. Simply ~ if the parents are carrying genetic material for hip dysplasia - so will the offspring. And the greater the genetic contribution for loose hips or malformed bone or abnormal muscle mass (Heritibility Factor) from the parents, the greater the chances for hip dysplasia in the offspring.
The expression of hip dysplasia in any dog has other determinants, though; genetics play only a varying role in the total picture. The effect of the developing dog's environment does play a role in the clinical (observable) signs of dysplasia, although just like the genetic component the effects of environment are variable and not completely understood. To illustrate the complexity of the environmental issue.
It is possible for a dog with known genetic components for hip dysplasia (called genotype) to not show any clinical signs of trouble if the environmental factors are favourable. So the dog can be dysplastic and not show observable signs of it until middle or old age.
It is always an important issue with breeders who assume that their dog is normal, just because it hasn't shown any signs of hip trouble.
Why take pelvic x-rays for dysplasia when the dog has always acted perfectly fit, they reason.
There is no excuse for NOT taking pre-breeding x-rays.
Two dogs that have the same genotype (genetic makeup) are exposed to different environmental conditions, their expression of hip trouble can be quite dissimilar.
Little wonder that the topic has such a wide range of information and misinformation regarding it.
Some of the environmental aspects that can affect the observable expression of hip dysplasia are the following: 1. Nutrition - There are reports that in puppies a restricted calorie intake could restricted the growth rate, and in turn will lessen the potential for the dog to develop hip dysplasia. (I wouldn't suggest doing this to any pup... it makes as much sense as stealing money from your own checking account!) The problem is that some restricted diets restrict the fat and protein content and increase the carbohydrate content of the food. Bad! The real goal should be to keep growing pups from becoming OVERWEIGHT. Restricting fat and protein in a growing pup can be a disaster. A high quality, meat-based diet is absolutely necessary for growing pups, just don't feed so much of it that the pup becomes overweight. 2. Physical Activity - In a young, growing dog with a genotype (genetic makeup) for CHD who will eventually develop some trouble because of it, will develop more arthritis and have more eventual difficulty if it is highly active physically. Climbing stairs, jumping into and out of pick-up trucks, running with other normal dogs can all subject the growing hip structures to unwarranted stress and trauma and increase future discomfort for the dog. The effects of this excessive activity is worsened in an overweight pup. (In a normal, growing dog, all these activities will not cause hip dysplasia!) 3. Bedding - There is no scientific proof, but lots of observational conclusions, that pups reared especially during the nursing period on slippery surfaces such as newspapers will be prone to hip difficulties. That is not to say that smooth concrete, wood or newspaper surfaces cause dysplasia, just that they can make a bad situation worse. Better surfaces for newborn pups would be blankets or towels... something they can get a better grip on. MUSCLE AND CHD: Research has shown that dogs with CHD have significantly decreased sizes of total pelvic musculature surrounding and acting on the hip joint.
Whether this is a contributing factor or a result of hip dysplasia remains to be proven.
One muscle that can contribute to worsening of hip dysplasia is the Pectineus Muscle. In dogs with a strong genetic background for CHD, the microscopic makeup and contractibility of the Pectineus Muscle are strikingly different from the same muscle of normal dogs. The theory is that a tight or inelastic Pectineus Muscle causes tension in such a direction that the force tends to pull the head of the femur away from the acetabulum. So the tight muscle creates more looseness in the joint. I have had good results in about 50% of the cases I have surgically excised a portion of the Pectineus Muscle. The patients were more comfortable and mobile almost immediately. This Pectineal Myotomy surgery has no effect on the arthritic changes in the hip joints; it can make the dog more comfortable. LIGAMENT OF THE HEAD OF THE FEMUR: Attaching to the head of the femur from the centre of the hip socket is a tough fibrous ligament called the Ligament of the Head of the Femur. If this ligament is stretched or torn, the hip joint will be less stable . . . and this is exactly what happens to dogs with dysplasia. In fact, some of the first changes to take place in young dogs developing hip dysplasia occur in this ligament especially if the muscle mass of the pelvis is underdeveloped. The ligament swells, develops tiny tears and stretches. In advanced CHD this ligament can totally break down and cause more harm than good.
JOINT CAPSULE: This tissue, which if you could hold it, would feel like the wall of a thick balloon It surrounds the joint and produces synovial fluid to nourish and lubricate the joint cartilage. In addition, the joint capsule provides some support to the joint.
In dysplastic joints the capsule becomes irritated, stretched, and scarred. In advanced cases the capsule will lose its elasticity and inhibit a full range of motion in the joint. A large percentage of the pain associated with hip dysplasia originates from inflamed nerve endings in the joint capsule so any pathology here will have a noticeable affect on the dog. CARTILAGE: The surfaces of the head of the femur and the acetabulum are covered with what is termed hyaline cartilage. In a dysplastic joint the points of pressure and the amount of pressure applied to areas of cartilage surfaces are abnormal. The cartilage is being asked to do things it physically cannot accomplish, so it changes or disintegrates as a response. The changes range from thickening in abnormal areas to thinning in others. Sometimes the pounding it gets erodes the cartilage down to the underlying bone! The outcome is more pain and discomfort, more inflammation, more calcium deposits from inadequate healing attempts and eventual breakdown of the joint as a unit.
Chondroitin Sulfate and Glucosamine may be effective in aiding the repair and maintenance of this articular cartilage.
BONE CHANGES: Since bone is alive it responds to stress and grows in a manner that tends to distribute weight loads evenly. As a result of posture changes brought on by discomfort, the dog's weight bearing forces stress the bone in unnatural ways. The bone does what it is supposed to do as a response and changes its shape. The bone doesn't know doesn't know that the shape it changes to is abnormal.
Ultimately, this abnormal shape to the thigh bone and acetabulum create more difficulty with stability and a vicious cycle ensues that spells trouble for the dog. The final outcome of bony remodelling in unstable hip joints is Degenerative Joint Disease.
SIGNS OF CHD IN YOUNG DOGS: What you will see first is a pup that runs with both back legs nearly together, almost like a rabbit would run. After exercise the pup will be reluctant to rise, will sit back as if unsteady and will have difficulty climbing stairs or inclines. The pup might look slightly underdeveloped in the rear quarters. When it stands the rear legs may not be parallel, but rather too near each other at the hocks (ankles) called "cow hocked".
You might notice a boniness to the pelvic area from lack of good muscle development. Another hint of trouble is an inability to extend the leg backward very far (decreased range of motion). Note: Many pups rest or sleep in a frog-like position with knees extended out to either side - this is a good sign and shouldn't alarm you. In severe cases of dysplasia, the young dog will rock forward to support more weight on the front legs (which can create trouble in the shoulders and elbows). When dogs do this it seems as if they are tip-toeing or walking very lightly on their rear legs. A dysplastic pup will be reluctant to jump or "stand up" on its hind legs. Signs usually being between five and eights months of age. But remember, as we learned above, some dogs do not show any signs at all of hip joint degeneration until mature adults X RAYING IN AUSTRALIA ~ INFORMATION SOURCED FROM A.V.A. The current system used for scoring radiographs for hip dysplasia in Australia is based the system devised and used by the BVA/KC. There are nine criteria to be evaluated. Scores between 0 and 6 are allocated for all criteria, except the caudal acetabular edge, for which the maximum score is 5. Higher scores indicate greater degrees of radiographic abnormality. The scores for the right and left joints are added to give a total hip score but the status of the worst individual hip is used for grading purposes where grading systems [as in Europe] are used. For a number of reasons it is not possible to rigidly standardise the information provided by the radiographic image of a complex structure such as the hip joint. Some of these reasons are:
Anthony [Tony] Scarcella P.O. Box 11. MILAWA 3678, VIC, Australia Phone : 0418540466 Email : gipfel1952@bigpond.com |
