Elbow disease Flashcards
Why are the individual pathologies in elbow dysplasia grouped?
Elbow dysplasia is a “catch all” diagnosis that is comprised of several similar, but separate, diagnoses for which the pathology is not as well understood. The different pathologies that make up elbow dysplasia tend to occur together, tend to occur in the same sorts of patients, and tend to occur at the same age. All have some similarities in diagnosis and treatment, and also tend to cause arthritis over time.
What are the individual components of elbow dysplasia?
- Ununited anconeal process (UAP)
- Fragmented medial coronoid (FCP)
- Osteochondritis dissecans (OCD)
- Joint incongruity
Label the structures of the elbow:
Where does OCD of the elbow generally occur?
Trochlear ridge of the medial humeral condyle
T/F: Incongruity is a thing that happens
TRUE (direct quote from Dundas)
Sometimes incongruity happens by itself and sometimes it happens in combination with other pathologies (particularly UAP and FCP); It’s a complex relationship, much like the long distance relationships of Ross students
What is the (simple) definition of incongruity?
Mismatch in articular surfaces
Can take many forms, including a discrepency in length between the radius and ulna
Why do uneven joint surfaces result in DJD?
Uneven joint surfaces –> uneven joint forces –> stress focused on specific areas of cartilage –> uneven wear on the cartilage –> DJD
T/F: The individual pathologies of elbow dysplasia always occur together
FALSE–may appear together or singly
It’s best to assume there are multiple problems in the joint and be pleasantly surprised when there aren’t
How does the phrase “developmental orthopedic disease” apply to patients with elbow dysplasia?
Elbow dysplasia is a developmental orthopedic disease, meaning it first manifests prior to skeletal maturity. Even when the lameness seems to resolve, these diseases often lead to secondary effects (leading to DJD in the long term). When patients present later in life it is due to the secondary effects rather than the primary
T/F: Dogs with elbow dysplasia should not be bred
TRUE
Elbow dysplasia is hereditary
Describe a typical patient with elbow dysplasia
- Young
- Male
- Large/giant breed dogs
T/F: Elbow disease is commonly seen bilaterally, meaning dogs should be screened for bilateral disease
TRUE
What is the typical history of a dog with elbow dysplasia?
- Must present from 5-12mo of age
- Chronic, progressive lameness
- Might be intermittent (aggravated by activity)
- Bilateral disease can mask lameness
T/F: Younger dogs might try to “power through” the lameness because they want to play, creating more subtle signs of elbow disease
TRUE
What are the typical PE findings in a dog with elbow dysplasia?
- Gait and posture
- Elbow lameness
- “Down on sound”
- Head drops as weight is put on the “good” leg
- Pain on manipulation of elbow joint
- UAP: pain on extension (anconeal pressure)
- FCP: flexion + supination (medial compartment)
- Thickening (fibrosis) in joint
- Crepitus on range of motion (if chronic)
What is the characteristic posture of elbow dysplasia?
Toes pointed out at an angle due to varying degree of external rotation of the antebrachium
Hold elbow in toward the body (adduction)
Postural changes serve to help offload the painful medial side of the joint, and shift the weight toward the lateral side
What is the proposed cause of UAP in general terms?
- Radioulnar incongruity–length discrepancy
- Shortened ulna displaces humerus proximally
- Excess force on developing anconeal process
- Ossification fails (disrupted microcirculation)
- Focused stresses –> separation
What is the proposed etiology of FCP?
Microtrauma
Presumed to be caused by incongruity
Diagnosis?
Ununited anconeal process
*Note the line of separation between the relatively large anconeal fragment and the underlying unla
**Flexed lateral view**
Diagnosis?
Osteochondrosis dissecans
Diagnosis?
IOHC
