Lameness localized to the elbow joint is usually the result of elbow dysplasia. The term dysplasia is used to define osteoarthrosis of the elbow resulting from one or more of the following: incongruence, ununited anconeal
process, fragmented coronoid process or osteochondritis dissecans (OCD) of the humeral condyle. Elbow dysplasia is a polygenetic
heritable disease in which one proposed pathogenesis includes incomplete ossification or bony fusion of the anconeus or medial
coronoid process to the rest of the ulna. Premature distal antebrachial growth plate closure also can lead to joint incongruence
and abnormal wear on articular surfaces.
Elbow dysplasia is common in rottweilers, Bernese mountain dogs, German shepherds, Labrador and golden retrievers and Newfoundlands
5 to 10 months old. Signs include intermittent or persistent weight-bearing forelimb lameness, a head-bobbing gait, decreased
range of motion and joint effusion. Affected dogs often have an elbows-out stance. Most dysplastic dogs have bilateral disease.
Radiography and computed tomography are used for diagnosis (Figure 2).
Figure 2: Radiographs of a young dog with elbow dysplasia—lateral (top left), craniocaudal (top right) and hyperflexed lateral
(immediately above) views are recommended. Note the osteophytes associated with the head of the radius and along the anconeal
process, the sclerosis of the ulnar notch and incongruence present and the small osteochondritis dissecans (OCD) lesion on
the medial humeral condyle indicated by the arrow.
Treatment can be medical or surgical but often involves both. Medical management consists of weight control, controlled exercise
and administration of NSAIDs, analgesics and chondroprotectives. Surgical management includes either open or arthroscopic
exploration of the joint, removal of fragments and débridement of fibrillated or malacic cartilage. It is imperative that
surgical treatment be followed with good medical management.
All dogs with elbow dysplasia develop arthritis over time and eventually demonstrate some degree of lameness. All will require
medical arthritic management for their lifetimes. Surgery is most helpful when dogs are young and still growing and have minimal
or no arthritis. Arthroscopy provides a minimally invasive means to explore the joint and treat several components of elbow
dysplasia with generally greater success than conventional surgical techniques.
The most common cause of forelimb lameness localized to the shoulder is OCD, which results from a disturbance of articular
or epiphyseal cartilage growth characterized by slow ossification of deep zone cartilage, leading to thickened, poorly nourished
articular cartilage susceptible to trauma experienced with normal weight-bearing. A dissection lesion develops between the
subchondral bone and articular cartilage, resulting in the characteristic flap.
Figure 3: A lateral radiograph of the shoulder in a young dog demonstrating flattening of the caudal humeral head consistent
with shoulder OCD (arrow). This view is best obtained under sedation to facilitate positioning so that the shoulder is not
superimposed over the thorax and sternum.
OCD affects large-breed dogs, including Labradors and golden retrievers, rottweilers, Saint Bernards, German shepherds and
Bernese mountain dogs, that are 5 to 10 months old. Most dogs with shoulder OCD have bilateral disease. Signs include forelimb
lameness, adduction of the elbow, muscle atrophy over the scapula and pain with flexion and extension of the shoulder. The
typical radiographic appearance is that of flattening and sclerosis of the caudal humeral head (Figure 3).
Figure 4: An arthroscopic image of the caudal humeral head with large OCD flap.
Treatment involves débridement of the cartilage flap and fragmented, malacic cartilage, followed by débridement of the lesion
to the subchondral, bleeding bone via an open arthrotomy or arthroscopy (Figure 4). Arthroscopy provides a minimally invasive
means to explore the entire shoulder joint, remove the cartilage flap and débride the cartilage defect with generally more
rapid recovery than conventional surgical techniques. The prognosis for a dog with an appropriately treated shoulder OCD is
good, and clinically significant osteoarthritis in the future is uncommon.
In part two of this series, I will review common causes of lameness in the hindlimb.
Dr. Janice Buback is a surgeon with Lakeshore Veterinary Specialists in Port Washington, Glendale and Oak Creek, Wis. She
and her family, including Angus and Pinot (a.k.a. "Steak and Wine"), enjoy working and playing in southeast Wisconsin.