Changes

The most common primary lesions are:

The most common primary lesions are:

:'''Osteochondritis dissecans''' (OCD)

:'''Osteochondritis dissecans''' ([[OCD]])

:'''Ununited Anconeal Process''' (UAP)

:'''Ununited Anconeal Process''' (UAP)

:'''Fragmented or Ununited Coronoid Process''' (FCP)

:'''Fragmented or Ununited Coronoid Process''' (FCP)

Primary lesions occur during the development of the puppy and usually occur in '''both elbows''' to the same degree.

Primary lesions occur during the development of the puppy and usually occur in '''both elbows''' to the same degree.

The primary lesions may stabilise when the dog reaches maturity, but further secondary lesions, most importantly '''osteoarthritis''', lead to irreversible changes and are a potential problem for the rest of the dog's life.

The primary lesions may stabilise when the dog reaches maturity, but further secondary lesions, most importantly '''[[osteoarthritis]]''', lead to irreversible changes and are a potential problem for the rest of the dog's life.

Elbow dysplasia is a multifactorial disease, but the most important cause is '''genetics'''. Other factors such as '''growth rate, diet and level of exercise''' may influence the severity of the disease slightly in an individual dog, but they cannot prevent the disease or reduce the potential of the dog to pass the disease on to offspring.  

Elbow dysplasia is a multifactorial disease, but the most important cause is '''genetics'''. Other factors such as '''growth rate, diet and level of exercise''' may influence the severity of the disease slightly in an individual dog, but they cannot prevent the disease or reduce the potential of the dog to pass the disease on to offspring. Studies show that elbow dysplasia has a high heritability confirming that a high proportion of the cause of the disease is genetic.   

 

However, studies show that elbow dysplasia has a high heritability confirming that a high proportion of the cause of the disease is genetic.   

In general, '''medium and large-breed dogs''' are more vulnerable to the disease, especially breeds such as German Shepherd Dogs, St Bernards and Labradors.

In general, '''medium and large-breed dogs''' are more vulnerable to the disease, especially breeds such as German Shepherd Dogs, St Bernards and Labradors.

===Osteochondrosis Dissecans===

===Osteochondrosis Dissecans===

This is '''failure of endochondral ossification''', which is usually more common in the [[Osteochondrosis|shoulder joint]].

This is '''failure of [[Bone & Cartilage Development - Anatomy & Physiology#2. Endochondral Ossification|endochondral ossification]]''', which is usually more common in the shoulder joint.

The condition tends to be '''bilateral''' and targets the '''medial condyle''' of the humerus. There is a subchondral bone cyst, a core of necrotic cartilage surrounded by a sclerotic layer.

The condition tends to be '''bilateral''' and targets the '''medial condyle''' of the humerus. There is a subchondral bone cyst, a core of necrotic cartilage surrounded by a sclerotic layer.

==Clinical Signs==

==Clinical Signs==

The clinical signs are of a '''variable lameness''', which is usually weight-bearing and worstens after long periods of rest or exercise.

The clinical signs are of a '''variable lameness''', which is usually weight-bearing and worsens after long periods of rest or exercise.

The may be '''swelling''' of the elbow joint.

There may be '''swelling''' of the elbow joint.

'''Secondary changes''' of degenerative joint disease may be felt as a bony thickening of the joint.

'''Secondary changes''' of [[Degenerative Joint Disease|degenerative joint disease]] may be felt as a bony thickening of the joint.

==Diagnosis==

==Diagnosis==

Different '''radiographic views''' allows detection of the abnormalities. The views include: extended lateral view, flexed lateral view and cranio-caudal view.

Different '''radiographic views''' allows detection of the abnormalities. The views include: extended lateral view, flexed lateral view and cranio-caudal view.

'''For elbow OCD''': the cartilage is not seen on radiography, but subchondral bone changes may indicate cartilage damage. Serial films may have to be taken several weeks apart to diagnos the condition. Changes may include subchondral bone lucency in the medial condyle (on the cranio-caudal view), subchondral sclerosis and calcification of the flap, osteophyte formation.

'''For elbow OCD''': the cartilage is not seen on radiography, but subchondral bone changes may indicate cartilage damage. Serial films may have to be taken several weeks apart to diagnose the condition. Changes may include subchondral bone lucency in the medial condyle (on the cranio-caudal view), subchondral sclerosis and calcification of the flap, osteophyte formation.

'''For UAP''': the flexed lateral view is the diagnostic view as it pulls the anconeal process out of the humerus. The condition is diagnosed if the anconeal process is ununited after 6 months of age. There may be degenerative joint disease on the joint margins.

'''For UAP''': the flexed lateral view is the diagnostic view as it pulls the anconeal process out of the humerus. The condition is diagnosed if the anconeal process is ununited after 6 months of age. There may be degenerative joint disease on the joint margins.

The third possible treatment is '''proximal diaphyseal ulnar osteotomy''': to restore congruency of the elbow and relieve the abnormal load of the anconeal process. This is most successful in young dogs.

The third possible treatment is '''proximal diaphyseal ulnar osteotomy''': to restore congruency of the elbow and relieve the abnormal load of the anconeal process. This is most successful in young dogs.

Prognosis is excellent if surgery is successful. Most dogs will show lameness at about 7 years of age.

Prognosis is excellent if surgery is successful but most dogs will show lameness at about 7 years of age.

Concommitant FCP or OCD dramatically alter the prognosis.

Concommitant FCP or OCD dramatically alter the prognosis.

Prognosis is guarded and poor if the condition is diagnosed after 1 year of age.

Prognosis is guarded and poor if the condition is diagnosed after 1 year of age.

'''Control of the condition''' involves radiographic screening of potential breeding animals and grading of elbows. Low-risk animals can then be '''selected for breeding''', thus reducing the heritability of the condition and significantly reducing the number of elbow dysplasia cases.

'''Control of the condition''' involves radiographic screening of potential breeding animals and grading of elbows. Low-risk animals can then be '''selected for breeding''', thus reducing the heritability of the condition and significantly reducing the number of elbow dysplasia cases.

[[Category:To Do - Helen]]

[[Category:To Do - Review]]

[[Category:Musculoskeletal Diseases - Dog]]

 

[[Category:Expert Review - Small Animal]]

[[Category:Joints - Developmental Pathology]]

[[Category:Joints - Developmental Pathology]]