Hip displasia                       

Displasia of hip is a genetic disease (heredable), congenital (present from the birth), degenerative that originates diverse degrees of arthritis, weakness in the later extremities and pain.

In a healthy joint, the head of femur perfectly fits in acetabulo or cavity to acetabular of the hip. In a coxofemoral joint with displasia, there is an alteration in the surfaces you will articulate (deformation of the cavity to acetabular and the head and neck of fémur). The contact lost between the surfaces you will articulate denominates subluxación; if the head of fémur slides outwards in partial or total form of acetábulo of the hip it denominates luxación.

The first passage in the development of the disease affects the cartilage to articulate of the hip, that loses thickness and elasticity, making difficult the absorption of the load during the movement. This loss of thickness of the cartilage can in the open leave completions nervous of the subcondrial bone causing pain. In an attempt to stabilize the union to diminish the pain, the animal produces new bone and the capsule to articulate engrosa, with which the mobility of troops is reduced.

It is not possible to be predicted when a dog with displasia will begin to show clinical signs of lack of mobility (swaying step, rigidity, cojera, difficulty to raise stairs, etc) due to the pain. There are numerous exogenous factors as the caloric contribution, the level of exercise or the meteorological time that can affect to the severity of the clinical signs and their fenotípica expression (radiográficos changes).

Displasia of hip is a disease of multifactorial origin (inheritance and diverse environmental factors as they can be the feeding, the physical exercise disturbed to early age, excessive weight and hormonal alterations). The heredabilidad is very high and of poligénica dominant transmission (intervention of several genes), which makes difficult to find a test genetic that it determines his presence. The only test on which it is counted at the present time is the radiográfico study.  

In the crossings between free individuals of displasia there is a high probability of producing puppies with good hips. The probability is increased based on the number of free ancestors of displasia known in previous generations.

The association of specialistic Spanish veterinarians in small animals (AVEPA) values and certifica the degree of displasia of hip by means of radiological study.

 

F.C.I	A.V.E.P.A	U.K.	E.E.U.U	NORMAL
A1	A: Free of displasia	0	E          Excellent
A2		0-6	G                 Good
B1	B :     Transition.	6-12	F                    Fair
B2		12-18	B         Borderline
C1	C: Slight signs of displasia	18-24	M                 Mild	DISPLASIA
C2		24-30
D1	D: Moderate signs of displasia	30-42	Mod      Moderate
D2		42-54
E1	E: Serious signs of displasia	54-66	S               Severe
E2		+ 66

 

     

In the United States, the fenotípica evaluation of hips classifies them in 7 categories:   Excellent E: classification assigned to the superior conformation in comparison with other animals of the same age and race. Acetábulo completely covers the head with fémur and the existing space between both is minimum. Good G: the union of the hip is correct. The head of fémur fits well in acetábulo and this one covers it satisfactorily. Regular F: smaller irregularities in the union of the hip exist. The space between the femoral head and acetábulo is ampler than in a good phenotype of hip. Indetermine B: agreement between the radiologists at the time of classifying these hips in the normal or displásica category does not exist. In order to increase the possibilities of making a correct diagnosis it is recommended to repeat the x-rays to the six months. Slight M: light subluxación is appraised (the head of fémur is partially outside acetábulo). Moderate Mod: the subluxación is more significant (the head of fémur as soon as it is based in acetábulo). Secondary arthritis is appraised, generally in the head and femoral neck, that will increase with the passage of time. Severe S: the subluxación is so that the head of femur is partial or completely outside acetábulo. Also secondary arthritis throughout the head and the femoral neck is appraised.   The Association of Specialistic Spanish Veterinarians in small animals (AVEPA) indicates that must be the breed club that determines that animals are correct for breeding with them, depending on the selection degree that is wanted to do. In most of the countries it is allowed to only raise with animals pertaining to the group A and B.

Source: Los Trastolillos.