Sx Diseases of the Stifle Objectives Flashcards
There are ___ cruciate ligaments in the stifle (knee)
2! Cranial and caudal
The cranial cruciate ligament arises from the ______ aspect of the
_______ femoral condyle,
and inserts on the _______ aspect of the region between the condyles.
The cranial cruciate ligament arises from the medial aspect of the
lateral femoral condyle,
and inserts on the cranial aspect of the region between the condyles.
The caudal cruciate arises from the _____ aspect of the _____ condyle,
and inserts on the _____ aspect of the intercondylar region.
The caudal cruciate arises from the lateral aspect of the medial condyle, and inserts on the caudal aspect of the intercondylar region.
Which ligament is indicated by the GREEN block?
Cranial cruciate ligament
Which ligament is indicated by the PINK block?
Caudal cruciate ligament
On this arthroscopic view, which ligament is
Cranial? Which is caudal?
Cranial = purple
Caudal = green
How are the cruciates named?
The cranial and caudal cruciate ligaments are designated as such based upon their distal component
I.E.: cranial cruciate ligament is so named because the distal portion (the insertion) sits cranially on the tibia relative to its proximal portion (the origin).
What is the relationship of the cruciate ligaments to the
synovial lining of the joint?
Ligaments are INSIDE the joint capsule, but OUTSIDE the synovial lining
“Intra-articular but extrasynovial”
Due to being intra-articular but extra-synovial, a damaged
cruciate disrupts the synovial barrier and is thus a
potent stimulus for ongoing _______ and there-by DJD
inflammation
What is the function of the cranial cruciate ligament?
prevents internal rotation, hyperextension, and tibial thrust.
the term usually used to refer to a force that causes the tibia to slide cranially relative to the femur
Cranial tibial thrust
What is the purpose of cranial tibial thrust?
Cranial tibial thrust is generated any time there is compression between the femur and the tibia (when weight applied to limb)
If the cranial cruciate ligament is intact, it opposes that cranial force
How does cranial tibial thrust relate to cruciate ligament rupture?
If the force of tibial thrust is greater than the breaking strength of the cruciate ligament = rupture
Most cruciate ruptures are a result of ____ tibial thrust forces applied to a cruciate ligament that is _____weak.
Most cruciate ruptures are a result of normal tibial thrust forces applied to a cruciate ligament that is abnormally weak.
What is the etiology of acute cranial cruciate ligament rupture?
Usually traumatic
In humans: They result from excessive torsion (rotation of the limb at the stifle) or extension on a normal, healthy CCL
In animals: almost always an acute aggravation of a chronic process
What is the etiology of chronic cranial cruciate ligament disease?
a chronically weakened cruciate ligament (due to a disease process) that cannot withstand the normal forces associated with weightbearing
In animals, which is more common:
Acute or Chronic cranial cruciate rupture/disease?
CHRONIC cranial cruciate dz is more common
What factors play a role in the pathogenesis of chronic cruciate ligament disease?
older age, weight (>15kg)
obesity, poor fitness,
conformation, excessive plateau angle
What is the risk of contralateral disease with chronic cruciate ligament disease?
Roughly 50% of dogs that blow one CCL as a result of chronic CCL disease will blow the other within 1‐2 years
Describe the signalment of the typical dog with cruciate ligament disease
Adult, large to giant breed,
FEMALE (slightly overrepresented), neutered dogs
Describe the history typical of chronic ligament disease
hindlimb lameness that is aggravated by activity OR after rest.
signs may be mild and episodic, with the lameness seeming to resolve between bouts (frayed rope analogy)
POOR response to NSAIDs and other arthritis drugs
(if DO respond to NSAIDs,
it is DJD responding and patient has advanced dz)
Describe the physical exam findings with cruciate ligament disease
Effusion behind patellar tendon
(if minimal effusion, patellar tendon divot is not palpable. if large effusion, stifle more rounded, normal “V” shape of the stifle obscured)
Distension→fibrotic change→disuse atrophy
Medial buttress
Crepitus
Tibial thrust (drawer test)
the accumulation of fibrosis along the medial collateral; a very firm, almost bone‐consistency lump on the medial aspect of the joint right where the medial collateral is.
Medial Buttress
The mainstay of a diagnosis of cruciate ligament rupture is the presence of _______ in the joint.
instability
(shown by tibial thrust on drawer test)
The _____and the _______ are two ways to test for cranial cruciate ligament rupture.
The cranial drawer test and the tibial compression test are two ways to test for cranial cruciate ligament rupture.
What is the difference between the two tests for cranial cruciate
ligament rupture?
The difference between the two tests is that the
cranial drawer test is testing the cranial cruciate ligament passively, i.e., without any effort from the patient.
The tibial compression test is testing the cranial cruciate actively, i.e., by simulating weightbearing.
T/F:
sedation is required to definitively test either cranial drawer or tibial compression
TRUE!
MUST sedate to be sure!
What is the significance of “puppy drawer” ?
Puppy drawer has an abrupt stop, where “standard” drawer has a softer, less well‐ defined stop.
can be a normal finding in a young patient (<6m).
If concerned with +test in young animal, look to see if effusion or pain
Describe the functional divisions of the Cranial CL
two subdivisions, the craniomedial band and the caudolateral band
craniomedial band is taut throughout the entire range of motion, caudolateral band is taut only in extension. (and lax in flexion)
This is a FUNCTIONAL division (NOT anatomical!)
How does disruption of one band (functional division)
affect the palpation findings
in partial vs. complete tears of the cruciate ligament?
With a partial tear, it is the craniomedial band that ruptures.
In this situation there will be a positive cranial drawer or tibial thrust, but ONLY when the joint is in partial flexion. When the stifle is in extension, it will appear stable.
T/F:
You should ALWAYS test for instability in the stifle joint
in BOTH flexion and extension
TRUE!
(could be a partial tear and could miss it if not)
How does treatment of a partial tear differ
from treatment of a complete tear?
IT DOESN’T