Sx Diseases of the Elbow Objectives Flashcards
List the individual components of elbow dysplasia
Ununited anconeal process (UAP);
Fragmented medial coronoid (FCP);
Osteochondritis dissecans (OCD); and
Joint incongruity
What components of elbow dysplasia are collectively
referred to as “Medial Compartmental Disease”?
Fragmented medial coronoid (FCP);
Osteochondritis dissecans (OCD); and
Joint incongruity.
anconeal and medial coronoid processes are part of this bone
ulna
where the humerus articulates with the ulna
trochlear (semilunar) notch
The anconeal process is the pointy bit at the _____ end of the trochlear notch. The coronoid process is the pointy bit at the _____ end of the notch.
Anconeal is proximal
Coronoid is distal
What is the location on the humeral condyle
where OCD of the elbow usually occurs?
trochlear ridge of the medial humeral condyle
elbow _______ is a mismatch in articular surfaces
incongruity
Elbow incongruity (radioulnar length discrepancy) is part of
the etiology of which two components of elbow dysplasia?
UAP and FCP
How does the phrase “developmental orthopedic disease” apply to
patients with elbow dysplasia? What does this have to do with
“biphasic age distribution”?
Developmental orthopedic disease is one that first manifests prior to skeletal maturity
Even when the lameness seems to resolve, these diseases often lead to secondary effects - joint disease which leads to DJD in the long run
When patients present later in life it is due to the secondary effects of the disease rather than the primary issue = Biphasic age distribution
For joint‐related developmental orthopedic diseases, the rule
“biphasic, bilateral, and heritable” always applies.
T/F:
Elbow dysplasia is hereditary
TRUE!
(so do not breed!)
Describe a typical patient with elbow dysplasia
elbow dysplasia is a developmental orthopedic disease so:
YOUNG, male, large/giant breed dogs
Is elbow dysplasia usually unilateral or bilateral?
Usually unilateral, but 35% of cases have bilateral disease, so it’s common!
. Describe the typical history of a dog with elbow dysplasia
chronic, progressive lameness.
It may be intermittent, only showing up after activity,
especially in the early phases.
How can bilateral elbow dysplasia mask lameness?
It will manifest not as lameness
but rather more as activity intolerance.
Younger dogs will still want to play and run, so difficult for owner to recognize
Describe the PE findings typical of elbow dysplasia
Gait exam (down on the sound) identifies the problem limb
Effusion in the elbow and pain on elbow manipulation
identifies the elbow as the source of the lameness
If chronic, may feel crepitus during ROM (because effusion leads to fibrosis)
What is the characteristic posture of dogs with elbow dysplasia?
Stand with their toes pointed out at an angle while holding
the elbow in toward the body (adduction)
All of these postural changes serve to help offload the painful
medial side of the joint, and shift the weight toward the lateral side.
Describe the proposed cause of UAP in general terms
elbow incongruity causes abnormal stresses on the developing anconeal process prevent it from fusing
What is the difference in ossification pattern of the ulna
between breeds susceptible to UAP and those that are not?
There is a separate center of ossification in the anconeal process
in breeds affected by UAP.
This center of ossification is not present in breeds that aren’t affected by UAP
The anconeal process is normally fused to the ulna by
___ weeks
20 weeks
What type of radiograph is necessary for diagnosis of UAP?
You need a flexed lateral view of the elbow to diagnose UAP
If the anconeal process remains separate from the ulna at ____ weeks,
it will not go on to fuse later, and is considered UAP!
24 weeks
What is the proposed etiology of FCP?
incongruity, as might happen with a shortened radius, is responsible for
microtrauma, which results in chronic overloading of the coronoid process
What are some radiographic findings in an animal with
UAP? What type of rad is required to see it?
Flexed lateral elbow rad
Note the line of separation between the relatively large anconeal fragment and the underlying ulna
any separation between the anconeal process and the ulna at 24 weeks of age or later is pretty much a slam dunk diagnosis
KNOW THIS!!!
What are some radiographic findings in an animal with
OCD? What type of rad is required to see it?
well‐positioned craniocaudal view of the elbow
a defect or divot in the bone of the joint surface which corresponds to a thickened section of articular cartilage
Sclerosis of the subchondral bone (manifests as bone that is whiter, or denser, than normal)
Describe the finding of OCD on the radiograph
white arrow in the left image points out a
small divot in the distal joint surface of the medial humeral condyle.
black arrow points to sclerosis
in the subchondral bone deep to the defect.
(The right image is much more subtle. If I ask you to identify an OCD lesion on an exam it will be based on a lesion more like the left image than the right.)
Describe the findings consistent with FCP on the lateral radiographs
A: medial coronoid process with indistinct margins
B: flattening of the medial coronoid
C: irregular margins
(D) is simply illustrating osteophytes in the region of the medial coronoid, which would occur once the secondary degenerative changes occur
Describe radiographic features of IOHC
Diagnosis of IOHC requires demonstration of the condylar fissure. This can usually be achieved with high quality craniocaudal radiographs of the elbow,
The fissure may be partial, only extending partway to the supratrochlear foramen, or it may be complete, extending all the way. It is important that IOHC is not mistakenly diagnosed on the basis of seeing a mach line – a visual anomaly created by the superimposition of one bone edge on another, which can appear as a radiolucent line through the condyle.
