Introduction

• Elbow dysplasia Elbow: dysplasia is a genetically influenced, inheritable developmental condition, involving multiple developmental abnormalities including medial coronoid disease (MCD) Elbow: medial coronoid process disease (MCPD), osteochondritis dissecans (OCD) Elbow: osteochondritis dissecans of the medial humeral condyle, ununited anconeal process (UAP) Ununited anconeal process and joint incongruity.
• MCD is a frequent cause of lameness in medium to large breed dogs and may manifest as fissuring or fragmentation of the medial aspect of the coronoid process (MCP), cartilage and/or subchondral bone.
• The exact cause of MCD is yet to be defined but elbow incongruity is suspected to be a primary contributor. Elbow incongruity is the anatomic misalignment of the articular surfaces of the humero-radial (HR), radio-ulnar (RU), and/or humero-ulnar (HU) joints.
• MCD may develop due to the undergrowth of the radius relative to the ulna (RU incongruity) resulting in an altered loading pattern on the medial compartment of the elbow. The resultant RU incongruity may also be consistent with the development of HR incongruity due to the relative increase in the HR joint space.
• An underdevelopment of the ulnar trochlear notch, and associated decrease in its radius of curvature, is also suspected of being a cause of MCD. This under-development with respect to the corresponding radial head and humeral condyle, may result in RU and HU incongruity respectively. This is turn may result in an increased load on the MCP and anconeal process.
• However, a relative increase in the radius of curvature of the ulnar trochlear notch has also been reported in dogs with elbow dysplasia and it maybe that a globally mis-shapen notch is responsible.
• Whatever the etio-pathogenesis, osteoarthritis Arthritis: osteoarthritis is a common sequela which may cause severe lameness in later life.
• There are many dogs with subclinical disease that have an increased risk of producing offspring with Elbow Dysplasia. These animals are not obvious and can only be detected by screening. Advanced imaging, such as CT, MRI or arthroscopy, is more sensitive than radiography in identifying these lesions but is impractical for a screening program.
•  Elbow dysplasia has a strong genetic component and therefore screening of dogs’ elbows by radiography and grading the changes will help breeders to select the most suitable dogs for breeding. Dogs should be at least one year of age; a similar requirement to those being screened for hip dysplasia.
• Radiographic screening programs, many of which are based on the International Elbow Working Group (IEWG http://www.vet-iewg.org/) guidelines, have helped to reduce the incidence of ED worldwide. In the UK the BVA/KC ED Scheme has been in existence since 1998 and has assessed over 250,000 X-rays since then. The scheme is open to all dogs and not just those registered with the Kennel Club. For the scheme to be meaningful and successful it is important that images from every dog radiographed be submitted for grading, regardless of whether the animal is required for breeding and whatever the state of the elbows. This is particularly important for the generation of estimated breeding values (EBVs) Breeding: estimated breeding values since the greater the number of dogs whose elbows are scored under the scheme, the more accurate the EBVs become.

Protocol for submission of radiographs to the BVA/KC Scheme

Radiography for ED assessment

Assessing radiographs

Use of the Scheme's information

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Burton N J, Owen M R, Kirk L S et al (2011) Conservative versus arthroscopic management for medial coronoid process disease in dogs: a prospective gait evaluation. Veterinary Surgery 40 (8), 972-980 PubMed.
• Temwichitr J, Leegwater P A & Hazewinkel H A (2010) Fragmented coronoid process in the dog: a heritable disease. Vet J 185 (2), 123-129 PubMed.
• Fitzpatrick N, Smith T J, Evans R B et al (2009) Radiographic and Arthroscopic Findings in the Elbow Joints of 263 Dogs with Medial Coronoid Disease. Veterinary Surgery 38 (2), 213-223 PubMed.
• Punke J P, Hulse D A, Kerwin S C et al (2009) Arthroscopic Documentation of Elbow Cartilage Pathology in Dogs with Clinical Lameness without Changes on Standard Radiographic Projections. Vet Surg 38 (2), 209-212 PubMed.

• Moores A P, Benigni L & Lamb C R (2008) Computed Tomography versus arthroscopy for detection of canine elbow dysplasia lesions. Vet Surg 37 (4), 390-398 PubMed.
• Berzon J L & Quick C B (2006) Fragmented coronoid process: anatomical, clinical, and radiographic considerations with case analyses. JAAHA 16 (2), 241-251 VetMedResource.
• Hornof W J, Wind A P, Wallack S T et al (2000) Canine elbow dysplasia. The early radiographic detection of fragmentation of the coronoid process. Vet Clin North Am Small Anim Pract 30 (2), 257-266 PubMed.
• Snaps F R, Balligand M H, Saunders J H et al (1997) Comparison of radiography, magnetic resonance imaging, and surgical findings in dogs with elbow dysplasia. Am J Vet Res 58 (12), 1367-1370 PubMed.
• (1995) International Elbow Working Group Protocol. Vet Radiol Ultra 36 (2), 172-173 Wiley Online.
• Olsson S E (1983) The early diagnosis of fragmented coronoid process and osteochondritis dissecans of the canine elbow joint. JAAHA 19 (5), 616-626 VetMedResource.