Dysplasia — congenital disease, which is based on heredity. And it spreads very quickly due to the use of certain conventional breeding methods, such as inbreeding, linebreeding. Basic seriousness of this disease lies in the so-called inheritance came loose hip, leading then, in addition to various stresses acting during the development of the animal to the underdevelopment of the acetabulum of the pelvic bone, which lies also underdeveloped and modified femoral head. Hip joint — mobile articulation of bones formed by the glenoid cavity of the pelvis (acetabulum) and the femoral head. Hip joint — a simple, triaxial, globular in shape.
Basic movement in the joint — flexion and extension, as well as rotation — are limited due to the structure and ligaments, articular structure of the relief and muscle. Extensive joint capsule, backed by strong ligaments that limit the scope of joint movement.
Hip dysplasia — a congenital abnormality when there is a subluxation of the hip joint, which is formed on the background of dislocation. This malformation captures all the elements of hip — acetabulum, the femoral head to the surrounding muscles, ligaments, capsule.
First hip dysplasia was described in 1935. Among the German Shepherd in the US, according Sheylsa, this flaw affects up to 75% of the dogs (1959), and served Henrickson — 7% (1969). According Shunkarda (1969) from 1962 to 1968 of 1,725 German Shepherd US forces 22.5% were culled because of this defect. Percentage of rejection close to fifty was obtained in the study of German Shepherds in almost all countries (Vamberg, 1967). According Shlaafa in 1971 in East Germany, this percentage was 35.8. The study, conducted at the site of greatest congestion dogs in Poland (Warsaw), revealed 21% of animals affected with dysplasia. According to statistics from the Nordic countries noted about 90% of dogs with clear symptoms of HD.
A number of species of HD reached, significant proliferation. Especially often amazed by her German Shepherds, St. Bernards, Newfoundlands, and of small dogs — Pekingese, affen-Pinschers and Pugs. This anomaly is also observed in Rottweilers, boxers, dogs, bulldogs, Beauceron while greyhounds are free from this defect. Depending disease of sex and age was observed.
Dysplasia in 89% of cases affects both hips, 3.3% — only the right hip joint, at 7.7% — only the joint of the left.
As etiological factors that lead to deviations from normal development TBS and the surrounding muscles, some authors consider it vice bookmarks, others — developmental delay TBS during intrauterine life of the fetus. Deviations of trying to explain the changes of vitamin balance, hormonal disorders and other causes.
There is an assumption that the development of HD is due to lack of interaction between an acetabulum and femoral head during intrauterine life of the fetus: the earlier the femoral head and the acetabulum are deprived of close contact with each other, the sharper manifest anatomical and clinical and radiological signs of dysplasia.
The emergence of the hip joint laxity has also been observed as the result of a kind of hormone games (estrogen) that seems most plausible evidence of disease pathogenesis.
Medical researchers have identified the majority of mothers who gave birth to children with hip dysplasia, the presence of cardiovascular disease or toxicosis of pregnancy, accompanied by disturbances of the protein and salt metabolism in the mother and fetus. Similar happens with our dogs.
Numerous studies have conclusively proven that hip dysplasia is a genetic, that is a hereditary disease. According to Mitin, its starting torque is transmitted hereditarily «factor of underdevelopment» of the joint.
Statistics of all the authors show that parents with severe degrees of the disease more percentage of pups with severe lesions.
In the question of the dependence of the disease on the sex of the animal scientists’ opinions diverge. Thus, according to Vanderlip (all breeds) males suffer 1.2 times more often. Tarkevich indicates an equal percentage of patients of both sexes (all breeds). According to Mitin (all breeds 1982) more incidence in females. But makes no reference to the characteristic entanglement with the floor, and hormonal influences. Served Dros (1991-1993 year) in German Shepherd dogs incidence of 25.4% and females — 28.5%. Thus, the figures given by various authors are quite close, and in all cases the percentage of patients in females is greater. When parents were free of dysplasia (selection in two generations), the percentage of healthy pups reached 76. If one of the partners was free of dysplasia, the percentage of healthy puppies ranged from 47 to 50. Bjorn-Force is considering the type of inheritance of HD as an autosomal dominant with probability of phenotypic expression of the gene in the population — 60%. In the emergence of HD plays a decisive role genetic predisposition. However, this disease can be observed in dogs, obtained from a completely unaffected parents. The degree of inheritance of HD according to the testimony of the Swedish authors is 55-60%. Statistical evaluation of the origin of the disease in the entire population of dogs is variable and depends on many factors.