Page 385 - Canine Lameness

20.4 Cooofemoral uoation 357

The most common type of CFLs is craniodorsal, comprising approximately 80% of all luxations.
Typically, luxation occurs when a supraphysiologic force is applied to the femur. This causes the
distal femur to be adducted, stretching/tearing the joint capsule and the ligament of the head of
the femur. Then, the femoral head slides over the dorsal rim of the acetabulum completing the
tearing of the ligament and the capsule. The gluteal and iliopsoas muscles act upon their insertion
at the greater and lesser trochanters causing the head of the femur to move craniodorsally. Ventral
luxation and caudodorsal luxation are rare. Ventral luxation most commonly occurs with a fall or
slip where the stifle is abducted rapidly. The femoral head may luxate into the obturator foramen
if the limb is rotated internally when it is luxating, or it may be adjacent to the pubis if the limb was
undergoing simultaneous external rotation of the limb when the luxation occurs.
Nonsurgical (closed reduction) and numerous surgical techniques (open reduction) have been
described for the treatment of CFL. Closed reduction is often attempted first in patients with nor-
mal anatomic configuration of the hip joint; however, this is associated with an approximately 50%
failure rate for single attempts at reduction. Historically, after closed reduction, it is recommended
that the limb be placed in an Ehmer sling for 10–14 days to prevent reluxation (McLaughlin 1995).
When a closed reduction fails, or there are concurrent orthopedic injuries (HD, pelvic fractures,
intra-articular fractures), open reduction with stabilization, total hip arthroplasty, or femoral head
and neck ostectomy is warranted.

20.4.1 Signalment and History

The majority of CFLs in dogs are the result of external trauma, with vehicular trauma composing
59–83% of cases (Bone et al. 1984; Basher et al. 1986; McLaughlin 1995). Trauma may happen to
any age or breed of dog; however, young intact male dogs are more likely to undergo vehicular
trauma. Dogs with HD are predisposed to both craniodorsal and ventral hip luxation compared to
dogs with normal hip coxofemoral joint conformation. Spontaneous luxations have been reported
in a series of dogs with minimal to no evidence of HD and no trauma (Trostel et al. 2000).

20.4.2 Physical Exam HIP REGION

CFL is often suspected based upon physical examination of the patient. Dogs will often present
non-weight-bearing on the affected limb, or non-ambulatory in the rear if they have sustained
bilateral CFL, which occurs in approximately 6% of cases (Basher et al. 1986). If any trauma was
associated with the injury, the entire patient should be assessed for stability prior to addressing any
luxation. Dogs may be intermittently weight-bearing if the luxation occurred sometime ago. In all
cases, severe discomfort and crepitus are present with range of motion of the hip.
With a craniodorsal luxation, the affected limb typically appears shorter than the contralateral
limb and is held with the thigh adducted rotating the stifle outward (externally) and the hock
inward (Video 20.1). On palpation of the hip region, the greater trochanter will be elevated com-
pared to the normal limb and there will be increased space between the greater trochanter and the
tuber ischii. In a normal non-luxated coxofemoral joint, palpation of the greater trochanter, the

Video 20.1:

Hip luxation gait.