Elbow dysplasia
The Ellenbogengelenksdysplasie ( ED ) is a chronically running disease complex of the elbow joint fast-growing breeds . ED is an inherited developmental disorder of the growing skeleton . High body mass growth and feeding errors are further favorable ( predisposing ) factors. ED begins in the late growth phase in four to eight month old young animals with a painful change in the joint and the joint-forming bone parts ( osteoarthritis ) with lameness . The range of motion of the elbow joint is restricted. Early signs are stiffness in the morning or after rest. The disease progresses lifelong and cannot be cured, but in many cases it is largely free from pain.
Occurrence and causes
Elbow dysplasia can occur in any large breed of dog. Most commonly affected are the Chow Chow , Rottweiler , Bernese Mountain Dog , Great Swiss Mountain Dog , Newfoundland Dog , Labrador Retriever , German Shepherd Dog and Bordeaux Mastiff . The frequency of occurrence ( prevalence ) is over 40% in some breeds.
ED is inherited polygenetically (through several genes ). The exact inheritance and the genes involved are not yet known, so that no genetic test for the disease exists. So far, proof can only be provided through the veterinary assessment of the individual animal, some dog breeding associations require an X-ray examination for breeding animals. The degree of heritability is greater for males than for females and is given as values between 0.1 and 0.7 depending on the breed and population.
Clinical symptoms
The diseased animals are conspicuous by lameness in the area of the forelimbs. There is a mixed form of lame leg and support leg lameness, often the forearm and paw are moved away from the normal axis of the limb ( abduction ) and the elbow is drawn towards the body ( adduction ), whereby the limb is twisted. During the clinical examination, an increased filling of the joint capsule can often be found, the joint is usually painful and sometimes grinding noises such as pseudo- crepitations can be triggered.
Manifestations
Elbow dysplasia occurs when the joint-forming bones of the upper arm bone ( humerus ), ulna ( ulna ) and radius ( radius ) do not fit together exactly enough. The imprecise fit or incongruence leads to chronic remodeling processes at the elbow joint and the joint-forming bone parts ( osteoarthritis ), which lead to sclerotherapy of the bones and the formation of osteophytes . If the joint surfaces are only slightly incongruent, osteoarthritis is the only sign of elbow dysplasia, and other changes can also occur:
- Fragmentation of the medial coronoid process (FCP, detachment of the inner coronary process of the ulna)
- Osteochondrosis dissecans on the condylus medialis humeri (OCD, cartilage detachment on the inner roll cusp of the humerus)
- Isolation of the processus anconaeus (IPA, detachment of the elbow process of the ulna)
It is common to have more than one of these complications at the same time. In the more recent literature, FCP and OCD are also summarized under the term Medial Compartment Disease (MCD). Occasionally, additional developmental disorders such as the lack of fusion of the three-side elbow are in German-speaking Verknöcherungskerne of the humerus, and the elbow congenital dislocation or subluxation at small (so-called chondrodystrophic belongs) breeds in the elbow dysplasia complex. The latter also favor the occurrence of an IPA or FCP, but are not counted as part of the ED complex by the International Elbow working Group .
Fragmentation of the medial ulna coronoid process (FCP)
Various mechanisms are discussed as the cause of the detachment of the medial coronoid process ( fragmented coronoid process , FCP ):
- Growth retardation of the spoke with shortening of the same ( short-radius syndrome ), which leads to increased strain on the ulna. At the medial coronoid process it is characterized for bone compaction ( sclerosis ), deformation and ultimately to detachment.
- Premature epiphyseal plate closure of the radial head.
- Disturbed fine blood flow (microvascularization) due to mechanically induced sclerosis of the bone in the area of the coronet process.
The disease occurs at the earliest between five and seven months of age. Under certain circumstances, however, the owner does not notice it immediately, so that animals are only presented to the vet when they are two years old. Clinically, an FCP manifests itself as lameness, which occurs mainly after prolonged rest or greater exertion. The elbow is exposed to the side.
The clinical examination reveals painfulness when the joint is greatly extended or flexed. In the X-ray image , the shadows in the ulna area, the loss of the trabeculae, an indistinct anterior contour in the latero-lateral beam path (lateral projection) and, if applicable, the fracture line of the process are visible. However, a complete avulsion of the coronoid process is rare. Due to the lack of congruence, a step between the radius and ulna and an unevenly wide joint space can appear. This incongruence occurs in 60% of patients with an FCP and can be represented using a quotient. For this purpose, the length of the trochlear notch and the distance between the tip of the anconeal process and the tip of the ulnar coronoid process are measured and divided. If the quotient of both values is above 1.15, the elbow joint is considered incongruent. The arthrosis associated with FCP manifests itself in more severe forms in lip formations of the adjacent bone contours. Bone attachments occur mainly on the inner (medial) edge of the ulna and the humerus. A reliable diagnosis of an FCP is rarely possible on the basis of an X-ray. Computed tomography and arthroscopy can support the FCP diagnosis.
Osteochondrosis dissecans humeri
A osteochondritis dissecans (OCD) is in the range of the elbow joint almost exclusively at the inner roll cusp of the upper arm bone ( medial condyle of the humerus ) in front. It usually arises at the age of 5 months and usually on both sides. More commonly affected breeds are Labrador Retrievers, Golden Retrievers, and Rottweilers.
This form of elbow dysplasia is often associated with a fragmented coronoid process . However, a "real" OCD is usually confused with the cartilage erosions ( kissing lesions ) in an FCP, which do not affect the (subchondral) bone tissue located under the articular cartilage, so that Read doubts the simultaneous occurrence of both lesions.
The diagnosis can usually be made on the basis of an X-ray image, especially in the anterior-posterior beam path (projection from front to back). However, X-ray evidence is not always successful, so that reliable exclusion can only be made using an arthroscopy or computer tomography (CT).
Isolated anconeal process (IPA)
An independent (isolated) elbow process of the ulna is a hereditary disorder of enchondral ossification and was first described in 1956. In the case of IPA, there is no fusion between the ulna and its anconeal process, which has its own ossification center , which usually fuses with the ulna between 18 and 24 weeks of age. At this age, there is a risk of partial or complete tear-off due to trauma or the failure of the joint to close due to high physical activity due to reduced elasticity . Another cause discussed is a reduced growth in length of the ulna (so-called short ulna syndrome ). An oversupply of calcium and phosphorus favors the occurrence of an IPA. Rottweilers and German Shepherds are affected above average. The disease is more common in males than in females. In about 60% of the cases, an IPA occurs unilaterally.
The diagnosis is made on the basis of an X-ray with the joint in the flexed position, whereby it should be noted that the anconeus process only fuses with the ulna at about six months. The fracture line is clearly visible in most cases, there is also sclerosis of the affected area and, with prolonged existence, bone extensions .
Classification
According to the International Elbow Working Group , ED is divided into three clinical stages depending on the extent of the disease. Here, only the severity of the osteoarthritis is assessed via the extent of the bone formation ( osteophytes ). The occurrence of specific lesions (FCP, IPA, OCD) is only noted, but not used for classification:
| Severity | criteria |
| Grade 0: normal | no osteophytes or sclerosis |
| Grade I: mild osteoarthritis | Osteophytes smaller than 2 mm or sclerosis of the articular surface ( incisura trochlearis ) of the ulna |
| Grade II: moderate osteoarthritis | Osteophytes between 2 and 5 mm in size |
| Grade III: Severe osteoarthritis | Osteophytes larger than 5 mm |
Another classification is the Lang ED score . A point classification is created here on the basis of various radiological features, with scores between 0 (no ED) and 21 (severe ED):
| feature | 0 points | 1 point | 2 points | 3 points |
| Osteophytes on Proc. anconeus | no | <2 mm | 2-5 mm | > 5 mm |
| Osteophytes in other locations | no | <2 mm | 2-5 mm | > 5 mm |
| Density inc. Trochlearis and radial head | inconspicuous | slightly increased | moderately increased | greatly increased |
| Congruence of the humeroulnar joint space, step formation between the radius and ulna | inconspicuous | Step <2 mm | Step <4 mm | Step> 4 mm |
| Proc. coronoid medialis | inconspicuous | - | abnormal shape | fragmented |
| Proc. anconeus | inconspicuous | - | abnormal structure or shape | isolated |
| Trochlea humeri | inconspicuous | - | Sclerosis, suspected OCD | significant OCD |
therapy
Detached skeletal (FCP and IPA) or cartilage parts (OCD) should be surgically removed, as they exert a constant stimulus on the joint capsule . This removal can be carried out via a joint opening ( arthrotomy ) or minimally invasive using arthroscopy and should be done as early as possible, i.e. before osteoarthritis develops. An IPA can also be fixed again by means of osteosynthesis . Then the animal should not be moved at all for two to four weeks if possible (leash, rest in the box) and then only little room to move for the same time. If there is also an incongruence in the joint, surgical removal of the detached fragments alone is not sufficient. Surgical cutting ( osteotomy ) of the ulna is usually performed here. In the meantime, a whole range of surgical techniques (distal dynamic ulnaostectomy, proximal dynamic ulnaostectomy, bi-oblique proximal dynamic ulnaostectomy, proximal abducting ulnar ostectomy, sliding humeral osteotomy) up to the insertion of an implant (canine unicompartemental elbow) have been developed. However, all surgical measures often do not prevent the progression of osteoarthritis. It can be used as a companion dog, but harder work such as working dogs is not recommended. An endoprosthesis may be indicated in severe elbow dysplasia . In the case of very severe changes, an endoprosthesis or stiffening of the elbow joint must be considered.
A pain reliever and anti-inflammatory therapy is useful. Here, mostly non-steroidal anti-inflammatory drugs such as carprofen are used. A study published in 2006 showed good tolerability of two-month therapy with carprofen in dogs and no evidence of toxicity to the kidneys or liver.
Weight reduction is strongly recommended for overweight animals.
The effectiveness of alternative medical treatments ( acupuncture , gold - implants , homeopathy ) has not been demonstrated in randomized controlled trials. A current evidence-based study could not prove any positive effects of electroacupuncture . A daily administration of gelatine as granules in the feed should prevent osteoarthritis or at least delay it.
Prevention and breeding measures
Dogs with ED should be excluded from breeding because of inheritance. For further control in breeding some associations carry out a breeding value assessment . For this purpose, x-rays are assessed by recognized experts. In principle, both elbow joints must be x-rayed and the animals must be at least twelve months old at the time of the examination. A lateral image (mediolateral beam path) in a 40–90 ° flexion position and a craniocaudal image in 15 ° supination are necessary for diagnosis. It is better to take two mediolateral images with flexion angles of 30 and 100–120 °, because this way an IPA can be more reliably detected.
Literature and Sources
- ^ S. Guthrie: Use of a radiographic scoring technique for the assessment of dogs with elbow osteochondrosis. In: J. Small Anim. Pract. 30, 1989, pp. 639-644.
- ↑ E. LaFond, GJ Breur, CC Austin: Breed Susceptibility for Developmental Orthopedic Diseases in Dogs. In: J. Am. Anim. Hosp. Assoc. 38, 2002, pp. 467-477. PMID 12220032 .
- ^ K. Maki, LL Janss, AF Groen, AE Liinamo, M. Ojala: An indication of major genes affecting hip and elbow dysplasia in four Finnish dog populations. In: Heredity. 92 (5), 2004, pp. 402-408. PMID 14997179 .
- ↑ K. Maki, AE Liinamo, M. Ojala: Estimates of genetic parameters for hip and elbow dysplasia in Finnish Rottweilers. In: Journal of Animal Science. 78 (5), 2000, pp. 1141-1148. PMID 10834565
- ^ A b L. Brunnberg: Lamenessdiagnostik in the dog. Examination, diagnosis, therapeutic advice. 1st edition. Blackwell Wissenschafts-Verlag, Berlin / Vienna 1999, ISBN 3-8263-3275-X .
- ↑ a b c d R. A. Read: Osteochondrosis and elbow arthrosis in young dogs: frequency, diagnosis and therapy. In: Waltham International Focus. 3 (2), 1993, pp. 2-10.
- ↑ Y. Samoy, B. Van Ryssen, I. Gielen, N. Walschot, H. van Bree: Review of the literature: elbow incongruity in the dog. In: Vet Comp Orthop Traumatol. 19 (1), 2006, pp. 1-8. PMID 16594537 .
- ^ A. Meyer-Lindenberg, M. Fehr, I. Nolte: Co-existence of ununited anconeal process and fragmented medial coronoid process of the ulna in the dog. In: J. Small Anim. Pract. 47 (2), 2006, pp. 61-65. PMID 16438692 .
- ^ A b Bruno Peirone and Fulvio Cappelari: Elbow dysplasia in dogs. In: Vet. Focus. 21, 2011, pp. 2-10.
- ↑ a b c P. Schawalder, H. Stich, T. Steidl, D. Spreng, E. Dietschi, H. Schmökel, U. Rytz: The elbow dysplasia in dogs. A clinical-synoptic approach to the different appearances with etiopathological considerations. Fragmented coronoid process and other forms of elbow dysplasia (part 2). In: Veterinary Spiegel. 1, 2002, pp. 14-27.
- ^ AP Wind: Elbow Incongruity and Developmental elbow diseases in the Dog: Part 1/2. In: J. Am. Anim. Hosp. Assoc. 22 (6), 1986, pp. 711-724.
- ^ A b J. P. Boulay: Fragmented medial coronoid process of the ulna in the dog. In: Vet. Clin. North Am. Small Anim. Pract. 28 (1), 1998, pp. 51-74. PMID 9463858
- ^ Michael Zwick et al: X-ray diagnosis of coronoid disease in dogs - an interobserver study. In: Small Animal Practice . 58, 2013, pp. 5-14.
- ^ A. Meyer-Lindenberg, M. Fehr, I. Nolte: The isolated processus anconaeus of the dog - occurrence, treatment and results. In: Small Animal Practice. 36/1991, pp. 671-679.
- ^ J. Lang et al .: Comparison of two classification protocols in the evaluation of elbow dysplasia in the dog. In: J. Small Anim. Pract. 39, 1998, pp. 169-174.
- ↑ L. Sjöstrom, H. Kasstrom, M. Kallberg: Ununited anconeal process in the dog. Pathogenesis and treatment by osteotomy of the ulna. In: Veterinary & Comparative Orthopedics & Traumatology. 8, 1995, pp. 170-176.
- ↑ GR Bouck, CW Miller, CL Teues: A comparison of surgical and medical treatment of fragmented coronoid process and osteochondrosis dissecans of the canine elbow. In: Veterinary & Comparative Orthopedics & Traumatology. 8, 1995, pp. 177-183.
- ^ MR Raekallio, AK Hielm-Bjorkman, J. Kejonen, HM Salonen, SM Sankari: Evaluation of adverse effects of long-term orally administered carprofen in dogs. In: J. Am. Vet. Med. Assoc. 228, 2006, pp. 876-880. PMID 16536696 .
- ↑ AS Kapatkin, M. Tomasic, J. Beech, C. Meadows, RC Boston, PD Mayhew, MY Powers, GK Smith: Effects of electrostimulated acupuncture on ground reaction forces and pain scores in dogs with chronic elbow joint arthritis. In: J. Am. Vet. Med. Assoc. 228 (9), 2006, pp. 1350-1354. PMID 16649937 .
- ↑ Bernd Tellhelm: Elbow dysplasia - ED X-ray technology and assessment. In: Small Animal Medicine. No. 5-2011, pp. 217-228.
