Elbow dysplasia
The elbow dysplasia (ED ) is a chronic disease complex extending the elbow joint fast-growing breeds. The ED is an inherited developmental disorder of the growing skeleton dar. High body mass growth and feeding errors are more favorable ( predisposing ) factors. The ED begins in the late growth phase at four to eight months old pups with a painful change of the joint and the joint bones forming parts (osteoarthritis ) with lameness. The range of motion of the elbow joint is limited. Early signs are stiffness in the morning or after rest. The disease live long gone and is not curable, a high degree of pain relief can also be achieved in many cases.
Occurrence and causes
An elbow dysplasia can occur in any large breed dog breeds. The most commonly affected are Chow Chow, Rottweiler, Bernese Mountain Dog, Greater Swiss Mountain Dog, Newfoundland, Labrador Retriever, German Shepherd Dog and Bordeaux mastiff. The frequency of occurrence ( prevalence) is in some races over 40%.
The ED is inherited polygenic ( several genes). The exact mode of inheritance and the genes involved are not known, so there is no genetic test for the disease exists. The proof can be carried out only on veterinary assessment of the individual animal thus far, some dog breeding associations are calling an X-ray examination for breeding animals. The degree of heritability ( heritability ) is greater for males than for females and is specified depending on the breed and population with values between 0.1 and 0.7.
Clinical symptoms
The diseased animals are conspicuous by lameness in the forelimb. Context, there is a hybrid of slope leg and supporting leg lameness, often there is a routing of the forearm and the paw of the normal axis of the limb (abduction ) and a pulling the elbow to the body ( adduction), where the limb is screwed. The clinical examination may often an increased filling of the joint capsule are detected, the joint is usually painful and partially crunching noises can be triggered as Pseudokrepitationen.
Manifestations
An elbow dysplasia occurs when the articulating bone parts humerus (humerus ), Elle ( ulna ) and radius (radius) is not sufficiently exact match. The imprecise fit or mismatch leads to chronic remodeling of the elbow joint and the pivot-forming bone parts (osteoarthritis ), which lead to sclerosis of the bone and the formation of bone outgrowths ( osteophytes ). At low incongruity of the joint surfaces, the Osteoarthritis is the only signs of elbow dysplasia, in addition, further changes may occur:
A simultaneous occurrence of several of these complications is frequent. In the recent literature FCP and OCD are summarized under the term Medial Compartment Disease (MCD ). Also other developmental disorders such as the lack of fusion of the three elbow Verknöcherungskerne side of the humerus and the innate Ellbogenluxation or subluxation in small ( so-called chondrodystrophic ) breeds in the complex elbow dysplasia are sometimes classified in the German-speaking countries. The latter also favor the occurrence of an IPA or FCP, but are not counted by the International Elbow working Group for ED complex.
Fragmentation of the medial coronoid process (FCP )
The cause of the detachment of the medial coronoid process (English fragmented coronoid process, FCP ) different mechanisms are discussed:
- Growth retardation of the spoke with shortening the same (short -radius syndrome ), which leads to an increased burden of Elle. At the medial coronoid process, this causes the bone compression ( sclerotherapy ), deformation and eventually to replace.
- Premature Epiphysenfugenschluss of the radial head.
- Disturbed fine blood flow ( microvasculature ) by a mechanically induced sclerosis of the bone in the area of Kronfortsatzes.
The disease occurs at the earliest at the age of five to seven months. Under certain circumstances, but it is not immediately noticed by the owner, so that animals are presented to the veterinarian until the second year of life. Clinically, it manifests as a FCP lameness that occurs mainly after prolonged rest or heavier loads. The elbow is exposed to the page.
On clinical examination, a pain shows in strong extension or flexion of the joint. Radiographically, especially the shading in the area of Elle, the loss of Knochenbälkchenzeichnung, an indistinct anterior contour in latero -lateral beam path (lateral projection ) and, if the fracture line of the extension are visible. However, complete demolition of the coronoid process is rare. Due to the lack of congruence is a step between the radius and ulna and a broad irregular joint space can represent. This mismatch can be represented by a quotient. For this purpose, the length of the trochlear notch and the distance between the tip of anconeal and the tip of the coronoid process of the ulna lateralis is measured. If the quotient of the two values above 1.15, the elbow joint is considered incongruent. Osteoarthritis associated with the FCP is reflected in more severe forms in lip developments of the adjacent bone contours. Exuberant bone occur mainly at the inner ( medial ) border of the ulna and humerus. A reliable diagnosis of FCP is rarely possible to the X-ray image. A computer tomography and arthroscopy may support the diagnosis FCP.
Osteochondritis dissecans of the humerus
Osteochondritis dissecans (OCD ) occurs in the region of the elbow joint almost exclusively to the inboard roll cusp of the upper arm bone ( medial condyle of the humerus ) ago. It occurs mostly on both sides at the age of 5 months and usually. More commonly affected breeds are Labrador Retrievers, Golden Retrievers and Rottweilers.
Often this form of elbow dysplasia is associated with a fragmented coronoid process. However, usually a "real " OCD with cartilage erosions ( kissing lesions ) is mistaken for a FCP, which do not affect the location beneath the cartilage ( subchondral ) bone tissue so that doubts Read a simultaneous occurrence of both lesions.
The diagnosis is usually based on an X-ray image filters ( projection from front to back ), especially in the anterior- posterior beam path. However, the radiographic evidence is not always possible, so that the safe exclusion can only be done via arthroscopy or computed tomography ( CT).
Insulated anconeal (IPA )
A stand-alone (isolated ) elbow extension of the ulna is a hereditary disorder of endochondral ossification and was first described in 1956. In the IPA, the merger between Elle and her processus remains under anconeal which has its own ossification center, which usually merges the ages of 18 to 24 weeks with the yard. At this age is due to a reduced elasticity of the risk of a partial or complete demolition by trauma or lack of joints circuit due to high physical activity. Another cause of a reduced longitudinal growth of the ulna ( the so-called short- ulna syndrome ) is discussed. An oversupply of calcium and phosphorus favors the occurrence of an IPA. Above average are affected Rottweiler and German Shepherd. In male dogs, the disease is more common than in bitches. Approximately 60 % of cases IPA occurs on one side.
The diagnosis is made in flexion of the joint by means of an X-ray image, it being noted that the processus anconeus until about six months fuses with the ulna. The fracture line is clearly visible in most cases, also leads to sclerosis of the affected area and prolonged existence to bone attachments.
Classification
According to the International Elbow working the ED Group is divided into three clinical stages, depending on the extent of the disease. Here, the severity of osteoarthritis of the extent of new bone ( osteophytes ), only assessed. The occurrence of specific lesions (FCP, IPA, OCD) is merely noted but not used for classification:
Another classification is the ED score after long Here is a points classification is created based on various radiological features, in which scores from 0 (no ED ) and 21 (severe ED ) result:
Therapy
Detached skeletal (FCP and IPA ) or cartilage pieces ( OCD) should be surgically removed, as they will exert a permanent stimulus to the joint capsule. This removal should be done as early as possible, ie before osteoarthritis develops. An IPA can be fixed again by means of osteosynthesis. Subsequently, the animal should be no movement of two to four weeks if possible ( leash, stall rest ) and then granted him for the same time very little room to move. In addition, where a incongruity in the joint, the surgical removal of the detached fragments alone is not sufficient. Here a surgical severing ( osteotomy ) of the ulna is performed mostly. All operational measures to prevent, however, often not the progression of osteoarthritis. Use as a companion dog is possible, of stronger labor as working dogs but are discouraged. In severe Ellbogendysplasien can be displayed an endoprosthesis. With very severe changes an endoprosthesis or a stiffening of the elbow joint must be considered.
In support is a pain and anti-inflammatory therapy useful. Here NSAIDs such as carprofen are used mostly. A study published in 2006 showed a good tolerability of a two-month therapy with carprofen in dogs and no evidence of toxicity to the kidneys or liver.
Weight reduction is recommended in overweight from pets.
The effectiveness of alternative medical treatments ( acupuncture, gold implants, homeopathy) has so far been proved not by randomized controlled trials. A recent evidence-based study showed no positive effect of electro-acupuncture. A daily administration of gelatin granules into the lining to prevent osteoarthritis or can at least delay.
Prevention measures and Breeding
Dogs with an ED should be excluded from breeding because of the heritability. To further combat in the breed genetic evaluation is performed by some associations. These radiographs are judged by recognized experts. In principle, both elbow joints are X-rayed and the animals must at the time of the investigation have an age of at least 12 months. For each diagnosis a lateral view ( mediolateral beam path ) in 40-90 ° flexion posture and a cranio-caudal in 15 ° supination are necessary. It is better to create two mediolateral shots with bending angles of 30 and 100-120 °, because as an IPA can prove is safe.