Page 345 - Canine Lameness

19.4 Cranial Cruciate igament Disease 317

frequent reasons for pelvic limb lameness in the dog. The condition has a complex multifactorial
etiology that is still incompletely understood (Griffon 2010; Comerford et al. 2011). Many factors
have been shown to play a role including genetics, environmental (e.g. obesity, timing of steriliza-
tion, and poor physical condition), and conformational (e.g. tibial plateau angle [TPA]). Immune-
mediated disease has also been suggested as an underlying cause.
While more research is needed to understand the etiopathology of CCLD, the clinical progres-
sion is well described – degenerative CCLD results in osteoarthritis of the stifle joint, in many cases
bilaterally. The progressive inflammation and degradation of intra-articular structures eventually
lead to gross joint instability and patient disability. As the CCL degenerates and global joint inflam-
mation worsens, traumatic and degenerative meniscal tears occur secondarily.
Successful treatment of degenerative CCLD has been reported with both surgical and nonsurgi-
cal strategies (Wucherer et al. 2013). However, surgical treatment has been suggested to be supe-
rior and TPLO is the preferred surgical technique (Wucherer et al. 2013; Bergh et al. 2014; Beer
et al. 2018). Treatment decisions should be made on an individual basis considering owner and
patient factors including the severity of clinical symptoms, age, size, systemic health, and activity
level of the patient. Meniscal tears frequently lead to more severe clinical symptoms. These tears
can be successfully addressed surgically with partial meniscectomy. Avulsion fractures can be
treated by reattachment of the avulsed bone or with proximal tibial epiphysiodesis (Vezzoni et al.
2008). The treatment of traumatic CCLD is similar to the treatment of degenerative CCLD.

19.4.1 Signalment and History STIFLE REGION
Degenerative CCLD most frequently affects dogs of approximately 3–7 years of age (Baker and Muir
2018). Commonly affected breeds include large-breeds such as Labrador Retrievers, Pit Bulls,
Rottweilers, Golden Retrievers, Chesapeake Bay Retrievers, Queensland Heelers, Akitas, Australian
Shepherds, Doodles, Bernese Mountain Dogs, Boxers, German Shepherds, and giant-breed dogs,
such as English Mastiffs, Newfoundlands, Landseers, Great Pyrenees, and St. Bernards (Duval
et al. 1999; Witsberger et al. 2008). Avulsion fractures are only observed in immature animals. Since
the attachment of the ligament to the bone is stronger than the immature bone in these patients,
the bone rather than the ligament itself “gives.” Traumatic CCLD is not well described in adult
patients, although the authors have observed this condition in agility and other sporting dogs. This
condition has to be differentiated from more severe traumatic injuries (e.g. stifle luxations) that
also cause disruption of other soft tissue structures (e.g. collateral ligaments and CaCL).
Patient history varies widely, from acute onset of severe lameness to insidious progressive lame-
ness which worsens with exercise or activity. Dogs may experience difficulty in rising or morning
stiffness consistent with stifle osteoarthritis as reported by owners. In dogs with patellar luxation,
CCLD may cause sudden worsening of the preexisting lameness. Waxing and waning of the lame-
ness severity may also be reported. This can be due to an initial, partial ligament tear and hemar-
throsis, with further tearing of the ligament until the entire ligament is disrupted in addition to
meniscal tears later in the disease stage. The progression through the disease stages varies greatly
in timeline with some dogs having an insidious, slowly worsening lameness that can progress over
years. Many of these cases maintain a partially intact CCL and meniscus and symptoms are due to
the osteoarthritic changes, rather than instability. A recent study showed that Boxers have higher
osteoarthritis scores compared to other commonly affected breeds (Gilbert et al. 2019), indicating
that they may have a longer duration of joint inflammation before presentation for diagnosis.
Other dogs progress rapidly from partial tears to complete tears, at which time the lameness fre-
quently becomes non-weight-bearing. Owners often perceive the condition as an acute, traumatic
event associated with a bout of activity or event (such as a dog park collision, stepping into a hole,