The most common orthopedic injury in dogs is the rupturing of
the cranial cruciate ligament (CCL), also known as the anterior
cruciate ligament (ACL). The cruciate ligament is located within
the stifle (knee). This joint is similar to a human knee in
that it is made up of the femur (thigh bone), tibia (shin bone),
patella (knee cap), and supporting tendons, ligaments, and
cartilage. The cruciate ligament is one of the main stabilizing
structures of the stifle because it prevents forward and
backward movement of the femur and tibia. When the cruciate
ligament tears or ruptures, these bones slide against each other
damaging other structures in the knee and causing chronic
arthritis.
Cruciate ruptures may occur during a single traumatic event,
but are more likely caused by a slow breakdown of the ligament
due to a predisposing factor such as anatomical abnormalities or
excessive slope of the top of the tibia. Clinical signs of early
cruciate disease include stiffness and mild lameness. As the
disease advances, lameness becomes more pronounce. A complete
cruciate tear initially results in a pet who is non-weight
bearing on the affected leg. As time passes, the dog may use the
leg, however the lameness will not resolve without surgery.
Our veterinarians diagnose cruciate tears during physical
examination by using a cranial drawer test. If the ligament is
ruptured, they can feel the femur slide across the tibia.
Radiographs are also used to ensure no bones are broken and also
to assess the extent of damage of the joint.
In most cases of ACL rupture, we recommend a surgical
procedure known as a TPLO (Tibial Plane Leveling Osteotomy) This
state of the art procedure was developed and patented by Dr.
Barclay Slocum of Eugene, Oregon. In order to perform this
procedure, veterinarians must complete Dr. Slocum's
certification course. Dr. Paul Young became certified and has
been successfully performing this procedure since 2004. Compared
to other ligament repair procedures, patients undergoing TPLO
surgery usually experience a more rapid recovery, a better range
of motion, less arthritic development, and more athletic
performance ability.
The basis of the TPLO procedure
is to level the tibial plateau which eliminates the use of
cruciate ligaments. In the dog, the top of the tibia is sloped.
This slope is known as the tibial plateau. The cruciate
ligaments stabilize the joint, so when the ligament ruptures the
femur slides down the tibial plateau. This sliding motion causes
the tibial plateau to thrust forward with each weight bearing
step resulting in pain and excessive wear on the cartilage pad,
known as the medial meniscus as well as other structures in the
joint.
During a TPLO procedure, a
special radial saw is used to make a curved cut in the tibia
bone. Next, the tibial plateau is rotated along the curved cut
to obtain a more level slope. The amount of rotation varies from
pet to pet. To determine the appropriate amount for each pet, we
use digital radiographs in conjunction with a detailed software
program. After the tibial plateau is rotated, a metal plate,
which is manually contoured by the surgeon to fit each pet, and
six screws are used to hold the bone together so it may heal in
its new position.
After surgery, owners must
restrict the pet's movement to ensure the bone heals normally.
Although the plate is extremely secure, quick movements or
severe strain on the leg could cause too much pressure on the
healing bone and result in a fracture. Ideally, the pet should
be confined to a crate and activity should be limited to walking
on flat surfaces, which means the pet can not climb stairs or
jump up on anything.
A fentanyl patch is applied prior
to surgery to help ease the pet's pain. Additional pain
medication and prophylactic antibiotics will also be sent home.
In some cases, pets may also be prescribed a mild sedative, such
as acepromazine. Along with giving medications, owners will also
need to periodically apply ice packs to the leg. After the
bandage is removed, the leg will also need to be gently massaged
and placed through range of motion exercises three times daily.
While short walks for elimination three to four times daily are
okay, no long walks or strenuous exercise is recommended during
the first four weeks of recovery. Throughout the recovery
process, our doctors will recheck the leg and monitor the pet's
progress. Radiographs will also be repeated eight and twelve
weeks after surgery to ensure the metal plate and screws are in
place and that the bone is healing correctly.
|
