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STANDARD SURGICAL REPAIR (DEANGELIS) PROCEDURE FOR CRANIAL CRUCIATE LIGAMENT RUPTURE
Dog and cat knees are similar to humans. For example, knees have five
ligaments, two menisci, a knee cap and joint cartilage. The ligament
most commonly affected in dog and cat knees- the cranial cruciate
ligament- is the same ligament most commonly damaged in professional
athletes. Dogs and cats usually tear this ligament when out running
around or sometimes when landing wrong after a jump.
The cranial cruciate ligament is a large, strong ligament located
within the knee joint. It is not actually a single structure, but is,
in fact, made up of a bundle of individual fibers tightly bound
together to form the ligament. Most of the time when the ligament is
injured, it is completely torn. Sometimes, only a portion of the
ligament will tear. Though only a portion of the ligament may be torn,
the whole ligament is damaged.
When a cranial cruciate ligament tears it causes sudden pain and often
results in the pet holding the affected leg up. It also causes
instability in the knee. Your pet may put the leg down and start using
it within a day or so, but will continue to limp for several weeks.
Normally, at the end of several weeks, the initial pain subsides and
the pet is willing to use the leg more; however, the joint remains
unstable. Every time the animal puts weight on the leg, the tibia (shin
bone) slides forward in relationship to the femur (thigh bone).
The abnormal motion causes wear and tear on the joint cartilage,
causing pain and arthritis. This motion can also put excessive stress
on the menisci ("C" shaped pieces of cartilage within the knee joint),
causing damage or tearing. An isolated meniscal tear can cause pain,
lameness and arthritis as well. Surgery is the only corrective measure
for cranial cruciate ligament injuries. The objective of surgery is to
stabilize the knee, allowing it to regain normal motion and thereby
reducing the formation of arthritis. Surgery has been and remains the
treatment of choice for this injury. If surgery is not performed,
progressive arthritis will occur and the lameness will worsen with
time.
There are many different ways to stabilize the knee with cruciate
ligament injury. The procedure that we typically use here is a
modification of the DeAngelis procedure, which involves placing heavy
gauge suture material from the back of the femur across the joint and
through a hole drilled in the tibia. The majority of animals will
regain normal or near .
normal use of their leg after the surgery and after a period of
rehabilitation. Strict limitations of strenuous activity combined with
controlled physical therapy is necessary after the surgery for a period
of six to eight weeks so that the animal rehabilitates the knee and leg
muscles and does not over stress the repair before the leg is ready for
full activity. Most dogs begin touching the leg to the ground in 10-14
days and are usually ready for full normal activity in six to eight
weeks. Complete recovery usually takes 3-4 months.
TIBIAL PLATEAU LEVELING OSTEOTOMY (TPLO) AND TIBIAL TUBEROSITY ADVANCEMENT (TTA)
TPLO is a surgical treatment for restoring limb function after a tear
of the cranial cruciate ligament. Dogs normally have a downward slope
on the top part of their shin bone (tibia) from front to rear. The
degree of this slope varies from dog to dog. The normal function of the
cruciate ligament is to keep the thigh bone (femur) sitting directly on
top of the shin bone. When the cranial cruciate ligament tears, the
thigh bone slides off the top of the slope of the shin bone towards the
back (downhill) side of the slope. Every time the dog puts weight on
the leg, the thigh bone partially "dislocates" as it slides down the
slope. This causes pain, instability and eventually arthritis.
The TPLO surgery levels the tibial slope so that when the dog puts
weight on the knee, the thigh bone remains centered on the top of the
shin bone eliminates cranial tibial thrust. Prior to surgery an x-ray
of the shin bone is taken and the angle of the slope is measured. An
incision is made in the skin along the inside of the knee and the top
of the shin bone. An incision is made into the joint and the meniscus
is inspected for tears. If found, these tears are removed—similar to a
person having the torn cartilage in their knee removed. A "C" shaped
cut is made into the top part of the shin bone. A calculation using the
preoperative degree of slope is then made and the top (cut) part of the
shin bone is rotated so that the slope in the bone becomes level. A
metal plate and screws are used to hold the bone in place. A nurse will
meet with you at the time of your pets release from
the hospital to review all home care instructions.
The bone heals in approximately eight weeks and during the
postoperative period, exercise must be limited. Patients are not
permitted to climb stairs, jump on furniture, play with other pets, run
around the house, or be off of a leash outside. Eight weeks
postoperatively, we take an x—ray to confirm that bone healing has
occurred. The rehabilitation process begins at eight weeks if the
osteotomy is completely healed. Slow short leash walks are preferred
for four weeks followed by an additional four weeks of controlled
activity on a long leash (optional). Full activity is usually possible
after the first eight to ten weeks of rest. We are very impressed how
well TPLO works for large, heavy and performance/athlete patients.
TTA and TPLO are similar in that both procedures stabilize the knee by
altering the biomechanical forces (cranial tibial thrust) that cause
the tibia (shin bone) to slide forward in relation to the femur (thigh
bone) during weight bearing. TPLO is accomplished by cutting the tibia
and flattening the slope of the joint surface. TTA is done by cutting
the front of the tibia and “advancing" the tibial tuberosity forward.
The tuberosity is maintained in is new location with a titanium plate
and titanium "cage" filled with bone graft. The following is a
comparison of TPLO and TTA.
ADVANTAGES OF TTA
l. TTA preserves the natural tibiofemoral articulation because the
tibial plateau is not repositioned as it is with TPLO. Consequently
natural load transmission across the menisci and cartilage is more
normal than with TPLO.
2. TTA reduces forces on the patella and the patella ligament thereby
eliminating the increased force on the patella ligament incurred
following TPLO.
3. TTA patients can be more active postoperatively than TPLO patients.
At the end of one week patients can walk one-half a block daily.
Distance can be increased by one block per week until released to full
activity (usually 8-14 weeks) (completely healed by l2 weeks).
4. Outcome of surgery is at least as good as TPLO (low case numbers and short follow up times in current studies).
DISADVANTAGES OF TTA
l. Unlike TPLO, TTA cannot correct tibial torsion.
2. TTA requires bone grafting.
3. Titanium implants are more expensive than TPLO implants (we charge the same for TTA and TPLO).
4. Many dogs have too much tibial slope to be corrected by TTA.
CONSIDERED ADVANTAGES OF TTA AND TPLO OVER LATERAL SUTURE TECHNIQUE (LST)
l. TTA and TPLO eliminate cranial tibial thrust with minimal alteration
to stifle range of motion. LST restricts flexion and internal rotation.
2. Rapid (2-3 days) return to weight bearing.
3. Three times less stifle osteoarthritis noted with TPLO and TTA compared to LST.
4. Excellent and more rapid recovery with TTA and TPLO especially in large, young or athletic patients.
Extracapsular Repair video
TPLO video
If you can't see the above videos get the VLC player (for Windows). Linux, Mac and others can find the viewer at videoLan.org .
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