116 Clinical Features
stifle arthritis, but a stable stifle with a partial
CR on further investigation.
Clinical signs
On physical examination, affected dogs usually
exhibit unilateral or bilateral weight-bearing
pelvic limb lameness. If the lameness is bilat-
eral, dogs will often lean forward and alter their
stance to unload the pelvic limbs (Figure 15.1).
Occasionally, a non weight-bearing lameness
may be evident. In dogs with unilateral lame-
ness, external rotation of the affected limb may
be evident when walking. Similarly, during
sitting, affected dogs will often position the
affected limb so that limb is externally rotated
and stifle flexion is reduced, compared with a
normal symmetric sitting posture. This is some-
times referred to as the ‘sit test’. In this posture,
the calcaneus is not directly underneath the
tuber ischii, because the stifle is not fully flexed.
On general examination, atrophy of pelvic limb
musculature in the affected limb(s) is usually
evident. Occasionally, an audible clicking may
be heard during walking or during stifle manip-
ulation, and is usually indicative of meniscal
damage, most commonly a bucket-handle tear.
Careful physical examination is important as
neurological disease may initially be suspected
in dogs that have difficulty rising from a sitting
to a standing position because of bilateral CR.
During examination of the stifle, effusion is
typically found, with the lateral and medial
margins of the patella tendon feeling indistinct
on palpation. Subtle effusion can be hard to
Figure 15.1 Photograph of a female Rottweiler with
bilateral pelvic limb lameness and bilateral cruciate
ligament rupture. Notice that she is leaning forward to
unload the pelvic limbs.
detect on physical examination, but is an impor-
tant clinical sign. Stifle radiography is a more
sensitive diagnostic test for stifle effusion than
physical examination. As CR is so prevalent,
if there is any uncertainty about this aspect
of stifle examination, bilateral orthogonal sti-
fle radiographs should be made in dogs with
pelvic limb lameness and examined for effusion
and arthritic degeneration. Radiographs also
underestimate pathological change, so an obvi-
ous stifle synovitis may be present, with only
subtle radiographic change. Even very mild sti-
fle synovial effusion should be considered an
important sign of partial CR (Chuanget al. 2014)
(see also Chapter 16).
Palpation of the medial side of the stifle will
often reveal a firm thickening, indicative of
periarticular fibrosis (Figure 15.2) or ‘medial
buttress.’ This pathological change is almost
always indicative of CR. Crepitation and resent-
ment to range of motion manipulation may be
found on flexion and extension of the stifle. CR
may also lead to excessive internal rotation of
the tibia relative to the femur, which may be
apparent on physical examination. In dogs with
partial CR and a stable stifle, internal rotation of
the tibia relative to the femur or stifle hyperex-
tension will usually elicit resentment as load is
applied to the CrCL with these joint manipula-
tions (see also Chapter 16).
Medial and lateral stress to the stifle should
also be applied during physical examination to
assess the stability of the collateral ligamentsFigure 15.2 Photograph of the medial aspect of the
right stifle. Prominent periarticular fibrosis of the stifle is
evident. It is important to check for firm swelling of the
medial aspect of the stifle or ‘medial buttress.’ This sign is
typical of chronic cruciate ligament rupture.