264 Surgical Treatment
Figure 31.2 Craniocaudal radiograph of a
Newfoundland with combined cruciate ligament rupture
and medial patella luxation. Femoral length is measured
as the distance from the proximal aspect of the
intercondylar fossa to the laterodistal aspect the femoral
neck (open circles). The anatomic axis of the femur is
drawn as the line connecting the center of two lines
drawn across of the femoral shaft at one-third and
one-half of femoral length. The distal joint reference line
is the line connecting the distal aspect of the medial and
lateral femoral condyles. The anatomic lateral distal
femoral angle (aLDFA) is the angle formed by the
anatomic axis of the femur (solid white line) and the
distal joint reference line. The mechanical axis of the
femur is drawn as the dotted line connecting the center of
the femoral head and the proximal aspect of the
intercondylar fossa. The mechanical lateral distal femoral
angle (mLDFA) is the angle formed by the mechanical
axis and the distal joint reference line. In this dog, the
aLDFA is 108◦and the mLDFA is 105◦. Both angles are
abnormally high.
torsion is assessed using an axial radiographic
view of the femur (Dudleyet al. 2006). This is
done by placing the patient in dorsal recum-
bency with the radiographic plate under the
hip region and by centering the radiographic
beam on the femur. CT scanning allows a tri-
dimensional assessment of the femur and tibia
(Harryssonet al. 2003), and greatly enhances
the repeatability of the assessment of angula-
tion and torsion of the femur and tibia, com-
pared to radiographs (Dudleyet al. 2006; Barnes
et al. 2015). The CT scan can be exported and
used to produce a replica of the bone to rehearse
surgery (Harryssonet al. 2003).Management
Management options are either non-surgical or
surgical. For Grade 1 PL with partial or com-
plete CR, focusing on quadriceps strengthen-
ing as part of a rehabilitation program could
be a viable option. A stifle brace may be con-
sidered, but little is known about the benefits
of braces. Braces are particularly challenging to
fit in small patients and in patients with short,
bulky limbs. Medium and large dogs can be fit-
ted with a brace and can be managed with con-
trolled activity and therapeutic exercises over a
period of 8–12 weeks. Physical rehabilitation of
dogs with CR is described in Chapter 42. Sur-
gical treatment of dogs with Grade 2, 3, or 4
PL combined with complete CR with meniscal
injury is generally required to regain stability of
the stifle joint. Several treatment options have
been reported which focus on realignment of
the quadriceps mechanism while stabilizing the
CrCL-deficient stifle. The surgery should pre-
vent cranial tibial thrust and torsional instabil-
ity (pivot shift) while maintaining normal range
of motion of the stifle joint.
Stabilization of the CrCL-deficient stifle joint
combined with PL is challenging because tech-
nical steps from both surgical procedures must
be combined when joint stability is surgically
reestablished. The trochlear groove is often
shallow, with a compromised medial or lateral
trochlear ridge. This may be developmental
or the result of wear caused by friction of the
patella on the trochlear ridge (Figure 31.4). To
restore patellar tracking, the trochlear groove
may need to be deepened; this is ideally