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Dealing with Cruciate Ligament Injuries in Labrador Retrievers
Chances
are your Labrador Retriever may have experienced a ruptured cranial
cruciate ligament (CCL). It’s the most common orthopedic injury seen
by veterinarians and is considered exceedingly common in Labradors.
Kurt Schulz, D.V.M., M.S.,
DACVS, associate professor of surgical and radiological sciences at
the University of California-Davis School of Veterinary Medicine,
says, “Labradors tend to be active
dogs that take part in a wide-range of sports. CCL tears are very
common in Labs. This may be due in part to a genetic disposition and
a tendency for less active dogs to become overweight. Unfortunately,
there is no known way of preventing CCL injuries, because we don’t
know the underlying cause. Controlling body weight is the single
most important step an owner can take to minimize the risk of this
problem. Moderate activity and fitness are beneficial.”
A
dog’s CCL is similar to the anterior cruciate ligament (ACL) in
humans. Located in a dog’s stifle (knee joint), the CCL plays a key
role in stabilizing the femur (thighbone) on the tibia (shinbone)
and allowing a dog to bear weight on his or her leg. “When the CCL
tears, the two bones are destabilized and the dog becomes lame,”
Schulz says. “Unless the injury is treated fairly quickly with
surgery, painful arthritis will likely set in.”
“Sometimes a
dog can tear its CCL either partially or completely as a result of a
traumatic injury like twisting or wrenching the knee,” Schulz says.
“But the ligament can also slowly stretch and tear over time,
resulting in a chronic, insidious injury. When that happens, a dog
might limp for a while but regain use of the leg until the complete
tear occurs and the dog is no longer able to put weight on the
leg.”
Determining CCL
Ruptures
If your dog starts to limp, you should take
him to the veterinarian immediately, Schulz recommends. “Early
treatment is important to stave off cartilage damage, which leads to
arthritis,” he says. “Since a cruciate tear doesn’t show up on
radiographs, in the vast majority of cases we don’t
X-ray.”
Instead, your veterinarian will likely evaluate the
way your dog is walking and palpate his legs, feeling the knee
carefully for any slipping, Schulz says. “Your veterinarian will
flex the knee to see whether the top of the tibia can be pulled
forward abnormally, like a drawer, indicating a CCL tear. Your
veterinarian may also pull the affected leg out to the side checking
for instability,” he says.
A partial cruciate tear doesn’t
necessarily result in instability. “If a portion of the ligament is
intact, the veterinarian may not feel the instability,” Schulz says.
“In that case, it is helpful for a veterinarian to view the ligament
either through surgery or arthroscopy, a procedure in which a small
camera is attached to a scope, for diagnosis of a cruciate problem.
For a definite diagnosis, it is important for a veterinarian to
either feel or see that the CCL is torn.”
During an initial
examination, a veterinarian should base treatment and recovery
recommendations on an individual dog, says Denis Marcellin-Little,
D.E.D.V., associate professor of orthopedic surgery at North
Carolina University College of Veterinary Medicine. “A dog’s fitness
level, the extent of the injury, the level of pain, and the
functioning of the joint all factor into the decision. Surgery is
important, but what happens before and after surgery will be
important as well.”
Surgical Options
Surgery to
stabilize the knee is usually the treatment of choice for dogs over
20 pounds, Schulz says. There are several types of surgery, and the
best choice will vary for an individual dog. Surgery may range from
$1,000 to $5,000. Surgical techniques used to repair CCL tears
include:
• Extra Capsular Suture: The conventional surgical
treatment, this procedure involves anchoring and tying a strong
surgical suture around the knee joint to restore normal position and
stability of the femur on the tibia. The procedure provides support
and performs a similar function as the cruciate ligament.
• Tibia
Plateau Leveling Osteotomy (TPLO): This procedure levels the slope
of the tibial plateau so the cruciate ligament isn’t necessary to
keep the femur from sliding down the plateau of the tibia. Surgery
involves cutting and rotating the top of the tibia, then screwing a
bone plate into place so the bone will heal in its new
position.
• Fibular Head Transposition: This technique uses the
lateral collateral ligament to do the work of the cruciate ligament.
The head of the fibula is rotated and the ligament is redirected to
mimic the cruciate ligament and is held in place with pins and
wires.
• Tibia Tuberosity Advancement (TTA): Similar to TPLO
surgery, TTA stabilizes the knee joint by changing the geometry and
physics of the knee and enabling it to work without a cruciate
ligament. TTA surgery may be less invasive and quicker than TPLO
surgery, but its long-term benefits have not been
assessed.
Surgical
Recovery
The good news about surgery for CCL ruptures
is that it is frequently curative, meaning a dog can go back to
normal use of his leg. The bad news is that the surgical recovery
takes from six to 14 weeks, and a dog must be quiet and controlled
during this time. Recovery depends on the body condition and age of
the dog and the surgical procedure
performed.
Though
it may be difficult to keep an active dog quiet for six weeks or
more, it is crucial, says Schulz, noting that consequences of
noncompliance are serious. “Allowing a dog to be active during
surgical recovery can lead to complete surgical failure, as well as
infection,” he says. “And if surgery fails, a second operation may
be necessary. There should be no running, jumping, falling or
slipping during recovery.”
Breeder Laura Michaels of
Flint, Mich., was concerned about surgical recovery
when her 4-year-old Labrador,
“Darby,” required a CCL repair in 2001. Michaels, who breeds under
Woodhaven Labradors, participates in agility with her dogs. She
thought she noticed a misstep when Darby was practicing weave poles,
then later that night noticed Darby was tentatively putting weight
on the leg. A visit to the veterinarian confirmed the diagnosis.
“I was frantic about the diagnosis and the thought of trying
to keep her quiet so long,” she recalls. “With six other dogs in the
house, I didn’t think I could do it. Darby had TPLO surgery, and the
recovery was swift and complete.”
Physical
Therapy
Post-surgical physical therapy and
rehabilitation are key in a dog’s ability to regain full function of
the knee joint, which is especially important for working Labradors. “Professional physical therapy can
be extremely helpful, but there is an additional cost,” Schulz
says.
“We recommend physical therapy at different intensity
levels, depending on factors like a dog’s fitness level and age,”
says Marcellin-Little. “It is far from being a cookbook approach.
While physical therapy can be beneficial, any activity your dog
performs post-surgery should be coordinated with your
veterinarian.”
Future
Injuries & Prevention
Unfortunately, once a dog
has had a cruciate injury in one knee, it’s not unusual for him to
have the same problem in the other knee. About 30 percent of dogs
that have surgery in one knee will require it in the other, Schulz
says.
In addition, a CCL tear can lead to injury of the
meniscus, the two cartilage cushions that sit inside the knee and
serve as shock absorbers when a dog walks. “If the meniscus tears,
it can very painful for the dog and must be treated surgically,”
Schulz says. “About 50 percent of completely torn cruciate ligaments
lead to meniscal injury. When the meniscus is torn, the knee will
make a characteristic popping sound when the dog is walking.”
Since there is no known way of preventing a CCL injury,
veterinarians speculate on prevention. “While it is believed there
may be a genetic connection in CCL tears, the exact connection isn’t
known,” Schulz says. “It is likely in the future we will identify
characteristics to avoid in breeding.”
In the meantime, it is
thought that carrying excess weight may place a dog at increased
risk for CCL injuries. “It makes sense that overweight dogs are at a
greater risk for CCL tears,” says Marcellin-Little, adding that it
has not been scientifically proven. “The most important thing owners
can do is to watch their dogs closely for limping or reluctance to
bear weight on their leg. The sooner a CCL injury is discovered, the
better.”
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