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simplest method for accomplishing this is removing
the articular surface and some subchondral until you have achieved the necessary depth. This defect will
fill in with fibrocartilage and has produced acceptable clinical results in dogs. Preservation of the majority of
the articular cartilage of the trochlear groove can be accomplished by recession tracheloplasty. A V-shaped wedge or block of the trochlear groove is removed with
a small saw. Additional subchondral bone is removed with a saw, curette or rongeurs, and the articular wedge is replaced into the defect. Pressure from the patella and friction generated between the wedge or block and the subchondral bone negate the need for internal fixation.
In young animals (<6 months old) the cartilage can be separated from the subchondral bone by gentle elevation with a periosteal elevator. The flap is replaced after sufficient subchondral bone is removed.
The tibial tuberosity is elevated and reattached to the proximal tibial in a position which is aligned with the femoral trochlea and extensor mechanism. Pin and tension band fixation is used to stabilize the tuberosity in its new position. This procedure can be used for both medial and lateral luxations. The quadriceps muscles can be released from the cranial portion of the femur
to better align the extensor mechanism. An additional procedure has been described advocating transposition of the rectus femoris muscle from its origin on the pelvis to the trochanteric crest of the femur. It is believed that this helps to better align the quadriceps muscle group as all other muscles in the group originate on the femur; however, it does require a separate incision and the dog must be positioned in lateral recumbency on the surgery table.
Correction of deformities of the tibia and femur are an important component of the surgical treatment of medial patellar luxation. These corrections should be done in young animals with remodeling potential, if possible. In older animals the entire limb has developed abnormally, with permanent bony and ligamentous abnormalities. Simply rotating the tibia medially or laterally does not correct these problems. Osteotomies are complex surgical procedures, but if performed by surgeon with experience can lead to excellent outcomes. Another strategy for correction of the tibial rotation is to use a heavy non-absorbable suture material from the fabella to the tibial tuberosity or distal patella. This technique is especially advantageous in dogs with combined medial patellar luxation and cranial cruciate ligament rupture as it also reduces craniocaudal laxity. Osteotomies such
as TPLO and TTA can also be used for treating medial patellar luxation and cranial cruciate ligament rupture. These techniques provide options for larger dogs with the combination of these two problems. Prognosis is highly dependent on the age of the animal at the time of treatment, the severity of bony changes that have developed, the severity of articular cartilage lesions
An Urban Experience
and the severity of degenerative joint disease that has developed.

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