Cranial Cruciate Ligament Rupture Black and White 2

Seattle Veterinary Specialists Clinical Update
CRANIAL CRUCIATE
LIGAMENT RUPTURE
Did you know
Approximately 50% of dogs will have rupture of both the right
and left CCL, typically within two years of each other
Cats can
suffer from
CCLR too!
Cranial cruciate ligament tears are rarely due to a single traumatic event. They occur due to
degeneration or weakening of the ligament over time, leading to partial or complete rupture.
Ligament degeneration has been shown to be genetic in Newfoundlands.
What is the CCL?
The cranial cruciate ligament (known as the anterior cruciate ligament, or ACL,
in humans) is one of several ligaments in the stifle (knee) that connect the femur
(thigh bone) to the tibia (shin bone). The CCL has 3 main functions: (1) prevent
cranial displacement of the tibia in relation to the femur (cranial drawer sign) (2)
prevent hyperextension of the knee, and (3) prevent internal rotation of the tibia.
Why does the CCL rupture?
Unlike in humans, rupture of the CCL in dogs is rarely the result of a traumatic
injury. Rather, animals tend to experience CCL “disease”, meaning that the
ligament degenerates or weakens over time due to genetic, conformational,
and/or immune mediated processes within the joint. The weakened ligament
may partially or completely rupture following activities such as running or
jumping. Unfortunately, the condition leading to CCLR is often present in both
knees, and about 30- 50% of dogs will rupture both CCLs within 1-2 years of
each other. CCL rupture is one of the most common orthopedic disease seen
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DIAGNOSTICS
dogs, and CCL repair is the most common orthopedic surgery performed by
veterinary surgeons.
Are any other parts of the joint affected when the CCL ruptures?
Quite often, yes. The medial meniscus (MM) is a fibrous pad attached to the top of
the tibia that acts as a cushion inside the joint (there is also a lateral meniscus, but
it is less often injured). The MM can be injured at the time of CCLR, but is more
often damaged after prolonged instability of the stifle joint. Without the support of
the CCL, the femur puts abnormal pressure on the MM, which can lead to tearing
or shredding of the meniscus.
What signs will I see if my dog ruptures a CCL?
There are three potential scenarios that can occur with CCLR: acute rupture,
chronic rupture, and partial tears.
Following an acute rupture, your dog will likely be painful and partial to non-weight
bearing lame in the affected hind limb. The lameness will likely improve over the
next several weeks; however, a sudden worsening may be seen if the MM
becomes damaged, and your dog will not return to normal
function without some evidence of lameness. An audible
clicking or popping may be heard if the MM is torn. With
chronic CCLR, an inciting incident may not have been
noticed, but persistent lameness is evident. Over time, the
body tries to stabilize the stifle by surrounding the joint with
CCLR is the
most common
orthopedic condition
treated by veterinary
surgeons
scar tissue. This will look like a swollen knee and range of
motion of the joint may be compromised. Arthritis will develop inside of the joint as
a result of chronic instability. Partial CCL ruptures are less obvious—your dog may
appear lame with exercise, but improves with rest. However, the ligament will
continue to weaken and the joint will become increasingly unstable. Eventually, the
ligament will likely rupture completely and lameness will not improve with rest.
How will a veterinarian diagnose a ruptured CCL?
The diagnosis of CCLR is typically based on the presence of the “cranial drawer
sign” and/ or “cranial tibial thrust”. In order to feel this, you dog will be placed on
his/ her side, and the veterinarian will feel the knee for cranial drawer motion. This
procedure is not painful; however, some dogs may be too tense to allow thorough
palpation. If this is the case, a sedative may be given in order to complete the
examination. Patients with chronic ruptures associated with a large amount of scar
tissue and arthritis may not exhibit cranial drawer. Other signs of CCL rupture
include palpable swelling of the joint, medial buttress (thickening or scarring on the
Diagnostic tests include a positive
“cranial drawer sign”, a positive “sit
test”, pain on extension of the stifle,
and radiographs to assess for joint
swelling and degree of arthritis
inside of the knee), discomfort on full extension of the stifle, and a positive “sit
test” (sitting with one leg held out to the side of the body rather than tucked
beneath). X-rays will also be taken in order to rule out other potential causes of
hind-limb lameness and to evaluate the extent of arthritis within the joint.
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Over 90% of dogs treated with TPLO surgery
return to excellent function
SURGICAL OPTIONS
FOR CCLR
What are my treatment options?
Surgical stabilization of the stifle joint is the treatment of choice for complete CCLR
in dogs. In addition to surgery, physical rehabilitation will be recommended.
There have been many different procedures described in order to treat CCLR. No
procedure completely halts the development of arthritis within the joint, but surgical
stabilization is believed to result in better functional results than conservative
therapy alone. The success rate with surgery is about 90% (meaning that nearly all
dogs return to good or excellent function following surgery and proper postoperative care). Regardless of the stabilization procedure, the stifle joint will be
explored and the MM will be examined and removed if damaged.
MRIT
The most common surgical options include:
Extra-capsular stabilizing suture (also known as lateral fabellar suture and modified
retinacular imbrication technique/ MRIT)
This procedure attempts to mimic the functions of the CCL by placing a heavy
gauge suture across the stifle joint in a similar orientation to the normal CCL. The
suture is placed on the outside of the joint but under the skin (extra-capsular).
Outcomes are very good in dogs weighing less than 30-40 pounds (and in cats). It is
possible to perform this procedure on larger dogs; however, the results are not as
predictable and breakage of the suture may be more likely.
TPLO (Tibial Plateau Leveling Osteotomy)
To date, the TPLO is considered by many experienced veterinary surgeons to be the
most successful stabilization procedure available for dogs of any size, and is
particularly successful in large dogs.
The TPLO changes the mechanics of the stifle joint rather than attempting to
replace or mimic the CCL with a graft or suture. The tibia has a natural slope, and
an intact CCL prevents the femur from “sliding” down the slope when a dog bears
weight. When the CCL is ruptured, the femur is free to slide down the slope, or in
other words, the tibia moves forward in relationship to the femur (cranial drawer)
when weight is place on the effected limb. In a TPLO procedure, the tibia is cut
(osteotomy) and rotated in order to flatten the tibial plateau (the top or joint surface
of the tibia) and prevent the femur from sliding backwards. A plate is applied to the
inside or medial surface of the tibia to stabilize the osteotomy. This procedure
requires specialized equipment and should be performed by surgeons experienced
with the technique. Proper post-operative management is critical in TPLO patients
since, essentially, a fracture has been created and the bone must heal.
Seattle Veterinary Specialists 425.823.9111
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TPLO
Activity restrictions are
essential for 2-3 months
following surgery. During this
time, walking and physical
rehabilitation exercises are
necessary for optimal
outcome.
www.svsvet.com
What will need to be done before my dog can have surgery?
X-rays must be taken prior to surgery. Routine x-rays are sufficient for dogs having extra-capsular repairs, but a special
view is needed for dogs having a TPLO surgery.
What happens in the hospital?
Your pet will need to remain in the hospital for the night following surgery for monitoring and in order to provide pain
medication. Immediately following surgery, therapeutic laser therapy can be performed over the incision and joint and has
been shown to speed healing and decrease pain and inflammation. Ice/compression applied to the knee joint every 6 hours
during hospitalization also helps to minimize swelling and pain.
What will the recovery process be?
You will receive detailed instructions at the time of discharge regarding post-operative care. Regardless of the procedure,
your dog will require at least 3 months of exercise restrictions. This will mean no running, jumping, or rough house play.
However, physical rehabilitation will be essential. Studies have shown that dogs who participate in a hydrotherapy-based
rehabilitation program return to function sooner than those that do not. A detailed program will be outlined for you and your
pet. In addition to clinic rehabilitation sessions, the program will
involve home exercises including leash walks of increasing duration
and therapeutic exercises to strengthen the muscles of the affected
leg as well as the core stabilizing muscles. Most dogs are allowed
to return to normal activity after 3-4 months (only once the bone
has healed completely and the muscles have been rebuilt). Failure
to follow the exercise restrictions dictated in the discharge
instructions could result in severe complications necessitating
further surgery.
Recheck appointments with the surgeon are required at 2
weeks, 8 weeks and 3 months after surgery. X-rays are taken at
the 2 and 3 month rechecks if a TPLO was performed to assess
bone healing.
What are potential complications of surgery?
Any time an animal (or human) undergoes anesthesia there is the risk of adverse reactions to anesthesia, including death.
However, blood work is performed prior to anesthesia in order to identify any underlying medical conditions that may
influence anesthetic choices or preclude surgery. In addition, there are board-certified anesthetists and an extremely
experienced staff of anesthesia nurses here at SVS that will take exceptional care of your pet.
Complications associated with surgery are uncommon and include excessive bleeding, infection, fracture of the
tibial crest or fibula, late meniscal tear, patellar tendinosis, and surgical implant failure. It will be essential that the postoperative instructions be followed precisely in order to prevent surgical site infections (usually due to dogs licking the
incision), failure of the suture or implant or fracture of tibia. Rare complications may require further surgery.
Michael Mison, DVM, DACVS & Kristin Kirkby, DVM, MS, CCRT, DACVS
Hours of Operation
For after hours emergencies contact
Seattle Veterinary Specialists
425.823.9111
11814 115th Avenue Northeast
Kirkland, WA 98034-6946
www.svsvet.com
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