Elbow dysplasia in dogs

Revised by Gary Clayton Jones BVetMed, DSAO, DVR, FRCVS with additional graphics by Jonathan Clayton Jones

The British Veterinary Association and The Kennel Club — working together for excellence in canine health dysplasia has been identified as a significant problem in many breeds. Importantly, the condition appears to be increasing worldwide. It begins in puppyhood, and can affect the dog

for the rest of its life The ‘flexed lateral’ view is a side on view of the elbow. This view allows examination of the secondary changes in ED which occur in the shaded areas. Note how some of the shaded areas here are overlaid by other structures, which makes them difficult to examine

eterinary surgeons have been to some extent. Once the dog reaches disease in that they have primary lesions aware for many years of a skeletal maturity the primary lesions or in their but number of conditions that may stabilise. However, once abnormal do not appear obviously lame. Some begin in puppies and cause development has started with a primary dogs will be symmetrically lame in each lameness.V was the first lesion, further secondary changes follow, foreleg, which can be very difficult to see. such disease to be widely recognised and in particular, abnormal wear of the joint Fortunately, these subclinical dogs can a scheme for its assessment and control surfaces and osteoarthritis (sometimes often be identified by taking radiographs is well established in the UK. Elbow termed arthrosis, or degenerative joint (x-ray films) of their elbows. Even though dysplasia (ED) is a significant problem in disease — DJD). The secondary lesions they appear to show no lameness many breeds worldwide, and although cannot be reversed and remain a potential themselves, they have a high chance of it begins in puppyhood it can continue problem for the rest of the dog’s life. producing lame offspring if they breed. to affect the dog for the rest of its life. The elbow is particularly vulnerable to The principal cause of ED lies in the this type of disease. The joint resembles genetic make up of the animal. Therefore, a hinge in which the and cartilage Causes of elbow dysplasia a scheme that screens animals for elbow forming each side of the joint have complex ED is a multifactorial disease, which means abnormalities will allow animals with shapes that fit together closely. The elbow that a number of factors can influence the best elbow joints to be chosen for has a wide range of joint movement and the occurrence of the condition. The most breeding, and will help to reduce the level normal foreleg gait is more dependent on important factor, however, is the genetic of the problem in the canine population. the elbow than the other joints. Thus, a make up of the dog. Other factors such as small change in the shape of one part of growth rate, diet and level of exercise may the joint can have major consequences for influence the severity of the disease in an Elbow dysplasia — the disease the joint function, like a small piece of grit individual dog, but they cannot prevent ED simply means ‘abnormal development of in a door hinge. Once elbow function is the disease or reduce the potential of the the elbow’. The term includes a number of affected, foreleg gait becomes altered. dog to pass on the disease to offspring. specific abnormalities that affect different An additional problem with ED is that However, studies show that ED has a sites within the joint. These cause problems lame dogs are only the tip of the ‘disease high heritability confirming that a high by affecting the growth of the cartilage iceberg’. Many dogs have subclinical proportion of the disease is genetic. which forms the surface of the joint or the structures around it. These abnormalities are primary lesions, which then induce a secondary osteoarthritic process. The most common primary lesions are: Dogs in which elbow Lame dogs dysplasia caused lameness are only the ● dissecans (OCD or OD) ‘tip of the iceberg’. ● Fragmented or ununited medial These animals are Subclinical dogs obvious because coronoid process (FCP) of their lameness. ● Ununited anconeal process (UAP) However, there are many dogs with subclinical disease that There are other, rarer, primary lesions Dogs with no radiographic have an increased risk of producing offspring that may occur in combination with these or clinical signs with elbow dysplasia. or on their own. Primary lesions begin These animals are not obvious and can early during the growth of the puppy, only be detected 2 and are commonly present in both elbows by screening As the individuals of each breed of dog have a proportion of their genetic make up (genotype) in common, it is not surprising that some breeds are more vulnerable to a heritable condition than others. In general, medium and large breed dogs are considered to be most vulnerable to ED, although the condition has been found in some smaller breeds. Unfortunately, ED is not controlled by a single gene or a simple inheritance. It is a polygenic characteristic, which means that it is controlled by the combination of many genes. One way of visualising this is to think of a ‘normal’ dog as carrying a few of the genes that can cause elbow problems. A dog with subclinical disease will have more of these problem genes, and a lame animal will have a higher proportion still.

Control of elbow dysplasia Primary abnormality. The arrow indicates an ununited anconeal process As the genotype is the overwhelming influence in the cause of ED, the disease can be controlled by minimising the views of each elbow joint are now problem genes within the population. This taken as described on page 4. Some common breeds means selecting sires and dams with the This ensures that most areas of the at risk are: best genotype. As yet there is no laboratory joint where abnormalities can be detected Basset Hound, Bernese Mountain test on blood or other tissue samples to can be examined. The radiographs are Dog, Dogue de Bordeaux, German enable us to select the best genotype. examined independently by two scrutineers Shepherd Dog, Great Dane, Irish However, dogs can be screened reasonably who look for primary lesions and any Water Spaniel, Irish Wolfhound, effectively by radiographing (x-raying) the signs of osteoarthritis. A grade is then Large Munsterlander, Mastiff, elbows and looking for the signs of ED. calculated for each elbow, based on the Newfoundland, Otterhound, If sires and dams are only selected from presence of primary lesions and the size Golden Retriever, Labrador animals with no or minimal ED, most and extent of the secondary lesions. The Retriever, Rottweiler, St Bernard of the clinical and subclinical animals overall grade is determined by the higher can be eliminated from the breeding of the two individual grades. Grades for programme, and so prevent them passing each elbow are not added together as they on their defective genetic make up to are for the two hips in the HD Scheme. the next generation. The success of such Identification of subclinical disease and screening depends on a high proportion its grade in either elbow is the important of the breed participating and making the factor in screening, so the grade of the information public so that low-risk animals worst elbow is always quoted as the overall can be selected for breeding. There is grade and is published on the progeny’s an international standard for screening Kennel Club registration documents and in schemes administered by the International the Kennel Club Breed Records Supplement. Elbow Working Group (IEWG), which The grading procedure and the records encourages a coordinated approach to are under continuous review and discussed the problem through regular meetings. at the annual CHS scrutineers' meeting, to enable changes in procedure to be made in light of new orthopaedic research, as Joint The UK elbow dysplasia scheme well as enabling publication of information space The Canine Health Schemes (CHS) is an for interested parties such as dog breeders association between the British Veterinary and geneticists. The scheme is represented Association (BVA) and the Kennel Club at IEWG meetings so that the UK keeps (KC) to run a screening scheme along pace with and participates in international Radius IEWG guidelines. Initially, schemes were development of management of ED. run by individual breed groups such as the Bernese Mountain Dog Club of Great Britain and the Guide Dogs for the Costs Blind Association, which were successful The owner is liable for their veterinary in reducing the incidence of ED. surgeon’s fee for anaesthetising the dog and taking the radiographs, as well as The 'extended lateral' view permits visualisation of some the CHS’ fee for the grading. The cost of the shaded areas obscured The grading procedure is currently reduced if hip dysplasia and by the 'flexed lateral' view. In this view, the position Although a number of different views elbow dysplasia films are submitted of the joint is similar to have been suggested, two radiographic for screening at the same time. that in the standing dog 3 Cover image © Eric Isselée, iStockphoto.com. Leaflet updated February 2014 The owner should sign the declaration (first part) of thecertificate, to verify the details are correct and grant permission for the use of the results.

● Once the radiographs are taken, the veterinary surgeon fills out the appropriate sectionof the form and submits both the radiographs and the form the to CHS. The results and the returned normally are radiographs theto veterinary surgeon within three weeks with a certificatefor the owner and a copy for the veterinary surgeon. Once a grade has been given for a dog, the radiograph cannot be owners have however, resubmitted; the right an to appeal, which takes the form of a re-appraisal of the original radiographs. A letter of appeal must be made within days 45 of the date of the original certificate. The whole procedure from initial appointment to receiving the grades is handled through the submitting veterinary surgeon. The Kennel Club Street Clarges 1–5 8AB W1J London Telephone 0844 4633 980 [email protected] www.thekennelclub.org.uk/doghealth

magazine Vet & Your Original article by Matthew Pead and Sue Guthrie, published in You change which characterise a normal joint show the clean lines and lack of secondary The dog must be at least one year old, but there is no upper age limit. The dog must be permanently and uniquely identified by way of a microchip or tattoo. registrationThe dog’s KC certificate and relatedany transfer certificates must be available so that the appropriate details can be printed on the radiographs. Microchip/tattoo numbers must also be printed on the radiographs. Radiographs of a normal elbow. These views

Getting a dog’s elbows graded Getting a dog’s Owners veterinary contact their should surgeon and arrange an appointment for their dog be to radiographed (x-rayed). The radiographs will usually be taken under anaesthesia or heavy sedation so the dog may have be to left at the radiographs Elbow practice. veterinary can be taken at the same time as those for the Hip CHS Dysplasia Scheme. When taking the dog for its radiographs following. the remember owners should ● ● ● ● There is a reduced fee when dog same the of radiographs are submitted simultaneously to the CHS for the Hip and DysplasiaElbow Schemes. For current fees and further contact:information please Schemes Health Canine Mansfield7 Street 9NQ W1G London Telephone 020 7908 6380 Email [email protected] www.bva.co.uk/chs

The grading system is simple: system The grading 0 = Normal 1 = Mild ED 2 = Moderate ED or a primary lesion 3 = Severe ED For further details see www.bva.co.uk/chs Diagnosis is normally based on lameness methodsTreatment vary depending on In some dogs, remove to mostHowever, dogs will be comfortable As is a prevalent ED disease, especially Treatment of clinical ED Dogs that clinical have often ED become lame between months age. of six and 12 Initially the lameness be may difficultto ascribe a particular to at joint. However, this age a persisting lameness should be investigated a veterinary by surgeon, as other conditions lead may similar to signs. with pain found on flexion and extensionof the elbow joint as well as joint enlargement. The animal a short have may or stilted gait as both limbs are often affected. Confirmationof the diagnosis is made findingby primary or secondary lesions on radiographs or the of other by elbow, investigations such as CT or . the nature and severity the of problem. Conservative treatment involving weight restriction and control exercise of is always important. Drugs be may used to relieve pain and inflammation, and may promote repair processes within the joint. fragments cartilage of and from the joint be may advised but this may not always be appropriate. In nearly all cases there will be some secondary changes which lead further to problems in the joint, and gradually may progress throughout the and life dog’s may restrict the ability dog’s exercise. to with level a fair exercise of if treated carefully during growth between six 18 to months age. of In severe cases it be may necessary consider to more major surgery. Advice on breeding The overall grade is used internationally as the basis breeding for advice. Ideally dogs with 'normal' (grade elbows 0) should be chosen and at least dogs withor 2 3 arthrosis should not be used breeding. for in the breeds listed on page such advice 3, will only be effective if it is continued over a number generations. of The most difficult partof acceptingsuch advicefor breedersmany is that some dogs have never been lame and exercise freely, but nevertheless high have may grades. This is the subclinical population with the ability pass to on the problem the in breed. For long-term control the of disease these dogs ought not be to bred from. 4