canine hip DySPLASIA

SUMMARY

Dysplasia coxofemoral is the bad formation of the articulations coxofemorais, happening in all of the races, mainly in the big ones and of fast growth. His/her transmission is hereditary, recessiva,intermitente and poligênica. Nutritional factors, biomecânicos and of environment, associates to the hereditariness, worsen the condition of the dysplasia. The suspicion to the clinical exam is possible, but it is the study radiográfico, usually starting from the twelve complete months of age in most of the races, by correct positioning of the animal, that it defines so much diagnóstico.Para the patient should be free from any reação.Este is reached with the general anesthesia, preferably. The patient should be positioned in number decubitus, members extended subsequent caudalmente, of equal length, parallel amongst themselves and in relationship á spine, rotacionados medialmente, in such a way that the patelas are put upon to the furrows trocleares. The pelve cannot be tilted. In the minimum identification of the film it should consist the number of registration of the dog, date of birth and it dates from the exam radiográfico. the subluxação, usually as first sign radiográfico, can take to the secondary artrose, denominated like this if it develops secondarily to another alteration, in the in case displasia.O controls of this bad formation is done through a selection radiográfica of all the animals used in the reprodução.O index of Norbeg is used for diagnóstico.Modernamente the treatment medicamentoso has if based on products with capacity anabolizante of the cartilage to articulate degenerate.

A diagnosis subject?

An appropriate clinical exam is not enough for the diagnosis of the dysplasia. Definitively it will be radiográfico, by quality image and animal correctly positioned.

Concept: it is the bad formation of the articulations coxofemorais. Index in all of the races, mainly in the big ones and of fast growth. He/she reaches the two sexes, could commit an articulation (approximately 10%) or both.

Histoy: Schnelle (1936) it described the dysplasia coxofemoral and Konde for the first time (1947) it commented on his/her hereditary origin. Schales (1959) it described her as bad formation and it indicated the exam radiográfico for the diagnosis. Wayne and Riser(1964) they related the fast and precocious growth and earnings of weight of German shepherds with genetic transmission. Henricson,Norberg and Olsson (1966) they considered her as bad hereditary formation and the subluxação as a consequence of the anatomical alteration.

Transmissão: hereditária,recessiva,intermitente and poligênica (some authors have been considering 20 genes). nutritional Factors, biomecânicos and of environment (multifatorial), associates to the hereditariness, worsen the condition of the displasia.Recomenda-if fundamentally to avoid the traumas, be them of the obesity, of the places escorregadios,etc...

Etiopatogenia: as structures that aid in the maintenance of the articulations are: capsule to articulate, ligament transverse acetabular, musculature of the area, round ligament, negative pressure to articulate and application of the acetábulo for the lip glenoidal or ligament acetabular.Pesquisadores has been basing their studies in the biochemical modifications of the liquid sinovial, as the decrease of the negative cloro(carga) and increase of the sodium and potassium (positive loads). In function of these alterations an increase of the osmolaridade, that brings as consequence the increase of the amount of the same liquid and the sinovite with dehydration of the cartilage to articulate happens. Starting from this instant a sequence of other episodes is uncoiled, such as: I increase of the pressure intra to articulate, I increase of the tension on the soft structures that it maintains the articulation, loosening of these soft fabrics, loss of the intimacy to articulate, arrasamento (ocificação or calcificação)ou not of the cavity acetabular (medial aspesto), subluxação (lateral displacement of the femoral head, usually as first sign radiográfico), edema, rupture partial or total of the round ligament, personal computer fractures criminal acetabulares and finally the secondary artrose (secondary because he/she grows secondarily to another alteration - the diplasia). There is to still consider the hypothesis that the dysplasia is a bad formation biomechanics, resulting from a disparity between the development of the pelvic muscular mass and the fast growth of the esqueleto (Illustration 1).


 Illustration 1. To the left drawing of an articulation normal and anomalous
coxofemural to the right. Forces articulate abnormal they tilt the head and femoral lap down,
they modify the anatomy of the cavity acetabular,rompem the round ligament and they thicken the femoral lap.

Symptomatology: it happens mainly among the four months until less than a year of life. The dogs can present dificul-dades to get up, to walk, to run, to jump and to go up stairways. The locomotion can be hindered in flat places. To run they can imitate the race of rabbits. The claudicação can affect an or two members. In the second case it is observed, with some frequency, that the animals move the more weight on the previous members, developing the musculature thoracic desproporcionalmente in relation to the subsequent ones. The last ones can be shorter, could happen reluctance to the exercises, being observed preference by the to sit down or to lie down. Abnormal episodes of aggressiveness are sometimes observed, besides with the proprietor. The dysplasia can provoke a lot of pains, to walk imperfeito,afetando the resistance of the animal.

Exam clínico: it´s made by the observation of the animal in station, walking and trotting, in the verification of increases of volumes and asymmetries and in the search of the presence of the pain, crackling and width of the movement to articulate, larger in the sharp and smaller phase in the chronicle, already in this last one they intensify the alterations articulate degenerative, taking place the capsular and muscular fibrosis surrounding. The signs Ortolani and Bardens should be explored in young dogs, anesthetized and put in lateral decubitus. For for the sign of Ortolani (Illustration 2), position the femur superior perpendicularmente to the longitudinal axis of the pelve and parallel to the surface of the exam table. Put the palm of one of the hands on the articulation coxofemoral under evaluation and with the another it holds the articulation corresponding fêmoro-tíbio-patelar firmly, pressing the femur against his/her acetábulo. When this pressure is exercised, the femoral head of the articulation dysplastic subluxa back-sidelong. Maintain this pressure and abduct to the maximum the femur. During this maneuver you will feel the head of the femur will return his/her cavity acetabular, sometimes emitting an audible sound similar to a" clunk." The return with or without sound it is found clinical that corresponds to a sign positive Ortolani, coming to confirm the presence of laxity to articulate. For the sign of Bardens (Illustration 3), suitable for lighter animals and with less than three months of age, hold the superior femur with a hand and position the other with the thumb in the tuberosidade isquiática, the indicator on the larger trocanter and the middle finger in the tuberosidade sacral. Abduct the femur parallel to the exam table. The lateral displacement of the larger trocanter, besides the compatible, noticed by the indicator, he/she reveals laxity to articulate.

Contention: the diagnosis is definitive through the exam radiográfico, by the patient's correct positioning and quality images. The positioning is usually reached through the general anesthesia, since we are front to a pathology many painful times and of races usually big. The pharmacological association of the tiletamina and zolazepam provides fast and deep analgesia and muscular relaxation. It is an anesthesia dissociativa holds, of reduced secondary effects. We recommended the administration in the dose prescribed by road E.V. (1ml for each 10 weight kg), due to the fastest effects (I win of tempo)e for the smaller doses, when compared to the application I.M.. The risks of an anesthesia done carefully and with modern drugs they fall practically to zero.

Control of the displasia: all of the animals used in the reproduction should pass for a selection radiográfica. As necessary minimum condition, at least the parents of the reproducers should be dysplasia insects, not being needs to stand out that the more far away we go in the control of the ascendancies, better approved animal será.Os for the reproduction will also owe him to be as the descendants' proof. It is not enough to present articulations normal coxofemorais, because the animals in these conditions can transmit the bad formation to their descendants. It is important to explain that the x-rays only evaluate the phenotypic aspects (alteration radiográficas) and no the genotype. Animal Freqüêntemente without dysplasia signs are bearers of the respective gens. It is necessary to leave very clear that all the animals, except for the ones of category THE, without signs of dysplasia coxofemoral(HD -), of German Hüftgelenk Dysplasie and English Hip Dysplasia,apresentam dysplasia, in minor or larger degree. Now in Brazil, for reproduction ends, the mating of the dogs belonging to the first three categories is allowed, in other words, A(HD -), B(HD + / -) and C(HD +), while some countries, as for instance Germany, they are only authorized for the same end the classifications THE and B. He/she suggests himself, in case the female is C (dysplasia light coxofemoral: HD +), that she should have excellent characteristics of the pattern of the race, as resignation, temperamento,etc.. These virtues should overcome the deficiencies of the articulations. This same female should couple with a male THE, without signs of dysplasia coxofemoral (HD -). The recommendations for the females should not be applied to the males, since the same ones will transmit the dysplasia for a very larger number of nestlings. Animals slightly dysplastic they tend to transmit discreet dysplasias. It is important to emphasize that the mating criteria should take into account the size of the plantel and the resignation of the articulations. If the population of animals in a certain race is very big and control and the control of the dysplasia is made rotineiramente there is a long time, the criterion in the reproduction will be more rigid if compared with other races with smaller number of copies and with the control more incipient radiográfico. Otherwise we would limit the matings that could not have so much more capable animals for this end. Many proprietors question diagnosis radiográfico, when the result is of dysplasia moderate or severe and when the corresponding dogs practice intense daily exercises without manifesting any symptom. That is perfectly possible, because we know that a lot of times there is no correlation between the lesions radiográficas and the clinical signs.


Illustration 4. Correct positioning of the dog for the diagnosis of the dysplasia.

X-ray perfeita: to take place a x-ray of the articulations coxofemorais for the diagnosis of the dysplasia, it is made neces-sária, preferentially, the general anesthesia, could be of short duration, in such a way that the patient is free from any reaction, with the objective of obtaining a correct positioning. The animal is put then in number decubitus (Illustration 4), with the members extended subsequent caudalmente, of equal length, parallel amongst themselves and in relation to the spine, rotacionados mediante,de such form that the patelas are put upon to the furrows trocleares. The pelve should be parallel to the surface of the table, in other words, without inclination. For a x-ray of appropriate positioning it is valuable a gutter, used to lie down the animal in his/her interior, with the pelve out of the same. Therefore she is a very important accessory for this exam type. The thoracic members are extended cranialmente, becoming the care of there not being inclination of the thorax of the animal. In these circumstances the image radiográfica should show us the following (Illustration 5):

The image radiográfica should allow the visualization of the whole pelve, as well as of the articulations fêmoro-tíbio-patelares,para that she can evaluate the symmetry of the ílios and the positionings of the patelas. If these have not put upon to the furrows trocleares, was ended that the subsequent ones were insufficient rotacionados or excessively. It is usually insufficient, in other words, the patela tends the if to put upon more to the lateral côndilo of the femur than to the furrow dito.No appropriate positioning of the patelas, reached properly through the medium rotation of the members, a force is exercised on the femoral heads, taking the dysplastic articulations to the subluxação, while the normal animal won't run the same. It is usually this subluxação the first alteration radiográfica and in beginning his/her more importante.Através is that he/she is determined the degree in the index of Norbeg. The other alterations will grow as a consequence of the subluxação, as for instance the artrose, for that denominated of artrose secundária.Uma quality x-ray should be well contrasted, being observed in a very detailed way the board number acetabular and the head's structure trabecular and femoral lap. They are reached these objectives been used good equipments of x-rays, it is crans and films of good origin, revelation for processing automatic whenever possible and a darkroom that it is really dark, provided of a lamp of safety that is really of safety. Under the surface of the table radiográfica, in Bucky, it is made present the grating anti-difusora, with the function of absorbing most of the secondary radiation. This, when he/she is absent, it produces images without contrast, that is, of filled with smoke aspect.


Illustration 5. I draw of the anatomical symmetry as consequence of a correct positioning.

Inadequate x-ray: it is that without appropriate positioning, characterized mainly by the asymmetry of the ílios, au-sência of parallelism among the femurs, mainly for abduction of the members, patelas no put upon to the furrows trocleares and those without image pattern, for they be sub or super exposed (egg whites or dark, respectively), harming the contrast, shaken, spotted, badly revealed, etc., as well as those without data of the patient's identification in the emulsão(antes of the revelação)do film.

Diagnosis: accomplished through the index of Norberg (Illustration 6). He/she bases on the determination of the centers of the femoral heads and of the union of the same ones through a line, that will make possible to draw us, starting from one of the centers a second line, that tangenciará the board acetabular lateral skull. The two lines form an angle amongst themselves, called angle of Norberg. This is just one of the necessary elements for the diagnosis of the dysplasia. Other factors should be taken into account, such as the positioning of the femoral head's center in relation to the board number acetabular, the aspect of the line to articulate, the presence of alterations articulate degenerative (secondary artrose) and the resignation of the boards acetabulares, mainly of the lateral skull. According to Norberg the smallest compatible angle with the normality is 105th, however it can have an articulation with 105th or more and to be classified as close of the normal (B) or slightly dysplastic (C), being Enough for this the osteófito presence in the board acetabular lateral skull, adulterating the angle or when less than 50% of the femoral head be inserted inside of the cavity acetabular. The authors have been extolling at least 50%. It is of fundamental importance to understand, that in beginning, as larger the angle of Norberg, adult will be the consistency to articulate. In other words, adult will be the contact between femoral head and cavity acetabular or adult will be the intimacy between them or larger ser'ao fits of the femoral head. Starting from this moment, as smaller the consistency to articulate, minor will be the angle and more evident it will be the subluxação, could reach until the dislocation.

There are some years the Brazilian School of Veterinary Radiology - CBRV, through a plêiade of doctors veterinary radiologists, has tornado reality, as in other countries, the emission of a Certificate of Control of the Dysplasia Canine Coxofemoral. This new services rendered modality appeared of a pressing need, since there was an enormous discrepancy among the accomplished diagnoses. These discrepancies took and they continue taking countless creators to incommensurable damages, since they found his/her creation supposedly in reproducers without dysplasia. CBRV, when receiving the x-ray accomplished by veterinary doctor, he/she examines her as the diagnostic quality, could return her, I marry the same doesn't obey to the demanded technical patterns.


Illustration 6. The sobreposição of a concentric circumferences to the
femoral head's limit will determine the referred femoral head's center.

Norms of CBRV for evaluation of the dysplasia coxofemoral in dogs in Brasil,segundo the criteria of the Federation International Cinológica - FCI

1 - Technical procedures

Age
 The evaluation of the conditions articulate will be done conclusivamente starting from the twelve complete months of age in most of the races, exception made to Bullmastiff, Dogue of Bordeaux, Great Harms, Leonberger,Maremma,Mastiff, Mastim Napolitan, Newfoundland,Landseer,Pyrenean Mountain Dog and St. Bernard, whose appreciation should be accomplished with at least eighteen complete months of age. Preliminary evaluations of the articulations coxofemorais can be accomplished starting from the six months of age.

Contention
 With the purpose of assuring the wanted technical quality, it is obligatory the patient's contention, by the use of pharmacological associations capable to determine perfect relaxation of the animal, to obtain the correct positioning and free from reactions on the part of the dog. The veterinary doctor, when accomplishing the x-ray, will sign an affidavit, committing with that contention type.

Positioning
 Number decubitus with the pelvic members in extension caudal, parallel amongst themselves and in relation to the column vertebral,tomando-if taken care of maintaining the articulations fêmoro-tíbio - patelares rotacionadas medialmente, in such a way that the patelas are put upon to the furrows trocleares.Deve-if still to be the careful for the pelve to be in horizontal position. A second x-ray will still be able to be used, with the pelvic members inflect-frog position (frog position).

Identification of the film
 In the permanent minimum identification of the film, in his/her emulsão,deverá to consist the number of registration of the animal, race, date of birth, it dates from the exam radiográfico and the identification of the articulation coxofemoral right or left.

The patient's identification
 The veterinary doctor when accomplishing the x-ray should identify the animal, case is not still, for microchip, correctly denominated of transponder(Figura 7), or for tattoo, for a subsequent control, if necessary.


Illustration 7. The transponder (microchip) it measures 11 x 2mm. His/her implantation
is subcutaneous, as any administration medicamentosa for the same road, dorsalmente to the encounter of the scapulas.

Size of the film
 It should be enough to include the whole pelve and the patient's articulations fêmoro-tíbio-patelares.

Quality of the x-ray
 The x-rays will be analyzed properly identified and the ones that obey the criteria of positioning of the animal, whose quality pattern offers conditions of visualization of the head's personal computer bone trabeculação and femoral lap and still definition needs the margins of the articulation coxofemoral, especially of the board number acetabular.

2 – Laud

The radiologist, when receiving the x-ray, appraised his/her quality for the diagnosis, being to his/her position the possibility of being returned to the veterinary doctor that accomplished her, in case it doesn't obey the wanted technical patterns. For the emission of the definitive decision, each x-ray will be examined by one of the radiologists accredited by CBRV, chosen for draw, that he/she won't have knowledge of the registration name or even of the proprietor of the animal. Each proprietor will be entitled, by payment of the respective costs, of appealing to one second and last diagnosis, submitted to the jury of the Displasia Coxofemoral of the Scientific committee of the Federation International Cinológica.

Classification of the articulations coxofemorais:

A (HD -): without signs of dysplasia coxofemoral (Illustration 8)
 The femoral head and the acetábulo are appropriate. The board acetabular lateral skull comes sharp and lightly round. The space to articulate it is narrow and regular. The angle acetabular, according to Norberg, is of aproximadamente105º, as reference.

B (HD +/-): articulations close coxofemorais of the normal (Illustration 9)
The femoral head and the acetábulo are lightly incongruous and the angle acetabular, according to Norberg, is of approximately 105th or the femoral head's center comes medialmente to the board number acetabular.

C (HD +): dysplasia light coxofemoral (Illustration 10)
The femoral head and the acetábulo are incongruous. The angle acetabular, according to Norberg, is of approximately 100th and/or there are a quick flattenings of the board acetabular lateral skull. They can be present irregularities or just small signs of alterations osteoartrósicas of the margin cranial acetabular, flow or number or in the femoral head.

D (HD ++): dysplasia moderate coxofemoral (Illustration 11)
Evident incongruity between femoral head and the acetábulo with subluxação. Angle acetabular, according to Noreberg, is larger than 90th, as reference. Presence of flattening of the board acetabular lateral skull and/or signs osteoartrósicos.

E (HD +++): displasia severe coxofemoral (Illustration 12)
 Marked dysplastic alterations of the articulations coxofemorais, as dislocation or different subluxação. Angle acetabular, according to Norberg, smaller than 90th. Evident flattening of the margin cranial acetabular, deformation of the femoral head (mushroom format, flat) or other osteoartrose signs.

 
 Illustration 8. The (HD -), without signs of dysplasia coxofemoral.
Illustration 9. B (HD + / -), articulation close coxofemoral of the normal.
Illustration 10.C (HD +),displasia coxofemoral leve.Discreta subluxação.
Illustration 11.D (HD ++),displasia moderate coxofemoral. Evident subluxação, accompanied of osteoartrose.
Illustration 12.E (HD +++), dysplasia severe coxofemoral. Subluxação still more evident, accompanied of osteoartrose.

Pré requesitos for the emission of the decision of dysplasia coxofemoral for CBRV:

Treatment: it can be medicamentoso or cirúrgico.Relacionam-if in this last several possibilities, from the simplest, such as, for instance, the pectineotomia and femoral head's ressecção (artroplastia excisional), until the most complex, as the corrections of deviations of the type valgus geno and antiversão, the triple osteotomia of pelve, the osteotomia intertrocantérica, the prolongation of femoral lap, the total prosthesis, etc., and the surgical associations, as femoral. Modernamente has if treaty, not only the dysplasia coxofemoral, but also the dysplasia of the elbow, the osteocondrose, head's femoral,a espondiloartrose avascular necrosis, finally, all of the pathologies articulate inflammatory degenerativas(artroses)e (arthritides) through products of natural origin with the property of regenerating (anabolizar)e to protect the cartilage to articulate degenerate, producing a natural analgesia. The steroidal anti-inflammatories chewed the pain, liberating the movements articulares.Estes steroids added to the movements articulate has a destruction action (catabolização)da cartilage to articulate, that it is antagonistic to the factors anabolizantes of the products above referred. For this reason the association of the same ones should not be recommended, much less only the application of the anti-inflammatories. The action anabolizante of the product can have a better when accompanied of appropriate measures of manejo,tais final result how to maintain the animal in restricted places so that the same reduces his/her physical activity, as well as avoiding the patient's obesity and the slippery places. There is the possibility to happen a remodelamento osteoarticular besides. This fact is of addition importance, because the osteófitos pericondrais could be, at least, partially reabsorbed, decompressed, for instance, the ramifications nervous located eferentes in the spaces intervertebrais. We could avoid the calcification of the disks interverterbrais.

In case these procedures are not crowned of success, we cannot stop considering the surgical intervention as an additional possibility.

Bibliographical references

1 - BRAUND, K.G. Hip dysplasia and degenerative myelopathy:marking the distinction in dogs.Veterináry Medicine, (aug.),1987.
2 - CORLEY,E.A.;KELLER,G.G.Hip dysplasia:a guide for dog breeders and owners. 2nd. edition, Orthopedic Foundation for Animals,1989.
3 - DOUGLAS, S.W.; WILLIANSON, H.D.Veterinary radiological interpretation.Philadelphia,Lea & Febiger,1970.
4 - ETTINGER,S.J.Textbook of veteranary internal medicine.Philadelphia,W.B. Saunders,p.2211-14,1983.
5 - FOX,S.M.;BURT, J. Symposium on hip dysplasia.Veterinary Medicine.p.684-716,1987.
6 - KEALY,J.K. Diagnostic radiology of the dog and cat.Philadelphia, W.B. Sanders,1987,p.352-362.
7 - MORGAN, J.P.; STEPHES, M. Radiographic diagnosis and control of canine dysplasia. Iowa State University Press, 1988.
8 - SMITH, G.K. et al. New concepts of coxofemoral joint stability and the development of a clinical stress-radiographic method for quantitating hip joint laxity in the dog. Journal of American Veterinary Medical Association, v.196,n.1, p.59-70,1990.
9 - THRALL, D.W.;LEBEL, J.L.Carlson's veterinary radiology. Philadelphia, Lea & Febiger,1977.
10 - TOMILINSON,J.; McLAUGHLIN. Jr., R.Canine hip dysplasia: developmental factors, clinical signs and initial examination steps.Veterinary Medicine, p.25-53,1996.
11 - TOMILINSON,J.; McLAUGHLIN. Jr., R.Medically managing canine hip dysplasia.Veterinary Medicine, p.48-53,1996.
12 - TOMILINSON,J.; McLAUGHLIN. Jr., R.Total hip replacement: the best treatment for dysplasia.Veterinary Medicine, p.118-143,1996.
13 - TOMILINSON,J.; McLAUGHLIN. Jr., R.Symposium on canine hip dysplasia. Veterinary Medicine, p.25-23,1996.
14 - TOMILINSON,J.; McLAUGHLIN. Jr., R.Actualidad en displasia coxofemoral. El perro ovejero     alemam,p.41-43,1997.
 15 - VERLAG, M.; SCHAPERH, H. Bercht der hüftgelenk dysplasia. Kleintier Praxis, n.23,p.169-180,1978.

Edgar Luiz Sommer - CRMV-SP nº 1556 1. Sócio proprietário do Provet, responsável pelos setores de radiologia, ultra-sonografia e ecocardiografia; Conselheiro do Conselho Regional de Medicina Veterinária do Estado de São Paulo; Diretor Secretário do Colégio Brasileiro de Radiologia Veterinária; Diretor pela América do Sul do International Veterinary Radiology Association.

Carlo Leonardo Grieco Fratocchi - CRMV-SP nº 7080 2. Presidente da Associação Brasileira de Radiologia Veterinária; membro do Colégio Brasileiro de Radiologia Veterinária; Radiologista do Provet; membro do International Veterinary Radiology Association.

 

Fonte deste artigo: Revista de Educação Continuada do CRMV-SP.
São Paulo, fascículo 1, volume 1, p.031-035, 1998.

Edgar Luiz Sommer - CRMV - SP 1556
Carlo Leonardo Grieco Fratocchi - CRMV - SP 708
Provet
Av. Aratãs, 1009
Cep: 04081-004 - São Paulo
SP -Brasil
provet@uol.com.br