Page 346 - Canine Lameness

318 19 Stifle Region

etc.). However, as stated above, traumatic CCLD is extremely rare; therefore, the traumatic event
perceived to coincide with the onset of injury is generally minor and only able to disrupt the liga-
ment because of previous weakening and degeneration. This is confirmed by the presence of radio-
graphic changes that indicate chronicity observed in these cases.

19.4.2 Physical Exam
A tentative diagnosis of CCLD can be established based on the specific physical exam findings
associated with the progression of CCLD outlined in Box 19.1. Although early in the disease stage
only some of these features may be present (e.g. joint effusion and pain on hyperextension), with
complete ruptures all features can be observed solidifying the diagnosis.

19.4.2.1 Postural and Gait Changes
Observation can be used to identify postural and gait changes associated with CCLD. Patients will
show varying degrees of lameness resulting in the classic features associated with pelvic limb lame-
ness (Videos 1.1. and 1.3). The lameness can be a subtle weight-bearing lameness at the trot that
worsens with exercise in the case of early stable disease or partial tears. Alternatively, it can also be
a severe weight-bearing lameness easily observable at the walk and trot. The lameness typically is
caused by an unwillingness to completely extend the stifle, which can help differentiate it from hip,
STIFLE REGION hock, or foot causes of lameness. Some dogs may avoid full ROM of the stifle by externally rotating

the stifle rather than flexing it. Dogs with meniscal tears or severe instability may be completely
non-weight-bearing.
Typically, patients will also offload the affected leg while standing, or offload the more acutely
painful side in bilaterally affected cases. This may be more obvious to observe than lameness dur-
ing motion in some cases (Video 1.1).
Lastly, several postural changes are observed with CCLD. The stifle may be kept flexed while
standing or during motion (Korvick et al. 1994) in an attempt to level the angle of the tibial plateau,
and the hock may be hyperextended to compensate for reduced stifle ROM and reduce the caudal
pull of the gastrocnemius muscle unit, which exacerbates tibial subluxation. Dogs with cranially
displaced meniscal tears may be unable to extend the stifle into a normal weight-bearing position.
When sitting, dogs with CCLD will sit with the affected stifle in extension due to the discomfort

Box 19.1 Progressive Physical Exam Findings Indicative of CCLD

1) Postural and gait changes
(a) Lameness and offloading of affected limb during stance
(b) Positive “Sit-test”
2) Palpation
(a) Stifle joint effusion
(b) Pain on hyperextension of the stifle joint
(c) Pain on flexion and loss of range of motion of the stifle joint
(d) Muscle atrophy
(e) Medial buttress
(f) Positive cranial drawer/tibial compression test
(g) Meniscal click