SIGNALMENT:
7-month-old male Pomeranian
HISTORY:
Abnormal hindlimb gait noted by the owner approximately one month ago.
Taken to referring veterinarian for examination.
DIAGNOSIS:
A diagnosis of bilateral medial patellar luxation was made, grade III/IV
on the left and grade II/IV on the right. Referred 5/99 for evaluation.
Physical examination along with radiographs of the pelvis and hindlimbs
(not shown) confirmed the referring veterinarian's diagnosis. Surgery was
scheduled for one month later when the dog would be 7 months of age.
TREATMENT:
The left knee was operated on 6/22/99. The first image (Figure 1)
is
of the trochlear groove, showing the flattening common with this condition. |
Figure 1
Intra-opeartive view from proximal to distal of the trochlea. Arrows
outline the extent of the medial and lateral trochlear ridges.
|
Figure 2
Intra-operative view from proximal to distal of the deepened trochlear
groove showing preservation of hyaline articular cartilage along the gliding
surface. The exposed bone along the lateral and medial edges will be covered
with fibrocartilage as it matures. |
Growth plates and juvenile articular cartilage respond to pressure
perpendicular to the physis or cartilage surface by cessation of growth,
or change in direction of primary growth according to the lines of pressure.
Since the patella did not sit normally in the trochlear groove, it failed
to develop a distrinct trochlear groove with ridges medially and laterally,
as can be seen by the lack of a distinct groove in Figure 1.
Figure 2 illustrates intra-operatively a deepened trochlear groove
using the trochlear wedge recession sulcoplasty technique. Note
that articular cartilage is preserved yet the groove is deepened.
ACKNOWLEDGMENT:
Thank you to Dr. Ken Coldwell, Veterinary Medical Center, for this
referral. |
