Page 364 - Canine Lameness
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336 19 Stifle Region
(A) (C) (E) (G)
(B) (D) (F) (H)
STIFLE REGION
Figure 19.17 Examples of (A–F) stifle luxation and (G, H) caudal cruciate ligament rupture: (A) lateral view
of a patient with stifle luxation. Note the multiple (white arrow) avulsion fragments indicative of severe
trauma; (B) stress radiograph of patient with disruption of both, the medial collateral ligament (MCL) and
lateral collateral ligament (LCL). Note the gapping of the lateral side and displacement that indicates
disruption of both ligaments; (C–E) patient with disruption of the CCL and LCL. Note the (white arrow)
avulsion fragment on the lateral view without evidence of displacement while the (D) varus-stress view
shows disruption of the LCL as identified by the (white arrow) gapping of the lateral joint; the valgus-stress
view shows that the MCL is functionally intact despite showing (white arrow) avulsion fragments indicating
that a partial disruption of the MCL is present; (F) valgus-stress view showing gapping of the medial joint
compartment indicating disruption of the MCL; (G, H) isolated caudal cruciate ligament rupture in an adult
patient. Note that the standard lateral view does not show evidence of osteoarthritis; mild joint effusion is
present. The stress view indicates caudal displacement of the tibia and also note the cranially displaced
(white arrow) popliteal sesamoid bone.
A fractured fibular head or avulsed fibular head indicates lateral collateral ligament instability.
On frontal view stress radiographs, the joint will gap open on the side with the torn collateral liga-
ment. Although advanced imaging can be performed to further classify the injury, it is rarely
needed.
19.7 Isolated Caudal Cruciate Ligament Rupture
Most CaCL injuries occur in conjunction with degeneration of the CCL. In fact, up to 88% of dogs
with degenerative CCLD also have damage to the CaCL via the degenerative effects of synovitis
and global joint inflammation (Sumner et al. 2010). The second most common cause of CaCL
