138 Clinical Features
(A) (B)F TFigure 19.6 (A) Hyperechoic, irregular tissue between the arrowheads is associated with synovial thickening. (B)
Irregular cortex of the tibia consistent with osteophyte formation (arrows). F, femur; T, tibia.
closer to the midsection or femoral attachment.
In chronic CR cases, the ultrasonographic fea-
tures seen are synovial hypertrophy, minimal
effusion, unless complicated by a meniscal tear,
and an irregular bone surface due to osteophyte
formation (Figure 19.6A,B). In chronic cases, an
irregular and thickened CrCL may be seen with
retraction of the ends at the site of the tear
(Figure 19.7). Occasionally, interstitial tears of
the CrCL (i.e., intact epiligament with internal
fibers disrupted) can be identified (Figure 19.8).
Meniscal tears are a common primary injury
in the human knee, but rarely occur as a primary
Figure 19.7 Irregular cranial cruciate ligament with
irregular ends (arrow) consistent with a complete rupture.
T, tibia.
stifle injury in dogs and are usually secondary
to CR. The occurrence of secondary meniscal
tears varies between studies, ranging from 10%
to 77% (Mahnet al. 2005; Thiemanet al. 2006;
Hayeset al. 2010). The risk of medial menis-
cal tears increases 12.9-fold with complete CR
(Hayeset al. 2010). There is an approximately
6% tear rate after surgical stabilization of the sti-
fle (Thiemanet al. 2006)
The ultrasonographic findings associated
with meniscal tears have been previously
reported as: (i) abnormal shape of the menis-
cus; (ii) increased fluid adjacent to the meniscus;
(iii) change in the echogenicity of the meniscus;
and (iv) displacement of the meniscus. The
most common abnormal appearance for a
meniscal tear is the flattening of the tibial sideFigure 19.8 Thickened and irregular cranial cruciate
ligament (arrowheads) with synovial hypertrophy and
fluid accumulation along the femoral trochlear notch
consistent with partial cruciate ligament rupture and
retraction of the ruptured fibers. F, femur; T, tibia.