118 Clinical Features
translation, whereas caudal drawer motion will
be elicited. Isolated rupture of the caudal cruci-
ate ligament (CaCL) is rare. A small proportion
of dogs affected with the CR condition and
diagnosed with CrCL rupture will also have
CaCL rupture. In CR dogs with rupture of both
cruciate ligaments, it can be particularly diffi-
cult to recognize that both cruciate ligaments
are ruptured during physical examination of
the stifle (Mightet al. 2013).
Conclusions
Detection of cranial drawer and cranial tibial
thrust on physical examination remains a key
part of patient investigation in dogs with CR.
However, the detection of stifle instability can
often be difficult to distinguish from mild lax-
ity, which might be normal in puppies, or a soft
stop to the cranial drawer test (Grade II sprain).
The cranial drawer test alone or in combina-
tion with the cranial tibial thrust test poorly
differentiates cranial and caudal cruciate rup-
ture in model studies (Mightet al. 2013). There-
fore, clinical findings from these tests should be
interpreted with caution and the diagnosis of
CR should also consider other physical exam-
ination findings and observations from other
diagnostic testing, particularly orthogonal sti-
fle radiographs. These limitations will likely
change in the future as knowledge of stifle
kinematics improves, as discussed elsewhere in
the book. Development of better teaching mod-
els for veterinary students may also enhance
clinical diagnosis of CR over time (Troy & Berg
2015). In future investigations, development of
a stifle arthrometer that objectively measures
subtle translation of the tibia relative to the
femur may aid early identification of dogs with
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