Page 362 - Canine Lameness

334 19 Stifle Region

Figure 19.15 Illustration of technique
used to obtain adequate positioned
craniocaudal radiographs of the femur
used to measure the degree of femoral
varus. The patient’s body is elevated of
the table to allow parallel positioning
of the femur to the detector.

STIFLE REGION

Wendelburg 2012). If the limb is rotated, the normal anatomy of the femur (mild varus and procur-
vatum) will give the (false) appearance of excessive varus deformity (Figure 19.16). Alternatively,
CT can be used to determine femoral varus and torsion (Dudley et al. 2006), as well to assess troch-
lear groove depth (Petazzoni et al. 2018). Therefore, in complex cases or for surgical planning, CT
may be quicker and more accurate than radiographs.

19.6 Stifle Luxation

Stifle luxation, also known as “deranged stifle,” happens secondary to severe trauma, especially
trauma that involves traction or torsion of the joint. Stifle luxation results in injuries to the soft
tissue stabilizers of the joint and can include disruption of one or both cruciate ligaments, one or
both collateral ligaments, and the meniscotibial ligaments/menisci. Unlike the cruciate ligaments,
the collateral ligaments of the stifle are very rarely individually injured in the dog. Therefore, any
collateral ligament instability should raise the index of suspicion for additional injuries. Treatment
of stifle luxation generally requires surgical reconstruction since the injuries are severe and result
in substantial stifle instability in multiple planes.

19.6.1 Signalment and History
Any dog can suffer from stifle luxation since it is caused by trauma. However, the condition is more
commonly seen in active medium- to large-breed dogs. Dogs that are free roaming or have the abil-
ity to escape to roam have an increased risk of vehicular trauma, a common cause of stifle luxa-
tions. Likewise, working dogs and hunting dogs are vulnerable to complex stifle injury from
interaction with livestock or due to rough terrain.