A cranial cruciate rupture is one of the most common orthopedic injuries seen in dogs. Sometimes known as a dog ACL, the cranial cruciate ligament (CCL), is a ligament in the knee that helps to connect the lower leg bone to the upper leg bone. Today our Waxhaw vets discuss why this ligament is prone to injury and how CCL ruptures are treated.
What is the cranial cruciate ligament?
One of two ligaments in the knee, the cranial cruciate ligament is a band of connective tissue that helps join the femur and tibia (the bones above and below the knee) and allows the knee to. It is also the ligament that is most prone to injury.
The cranial cruciate ligament in dogs is similar to the anterior cruciate ligament (ACL) in humans and much like the rupture of the cruciate ligament in dogs, humans regularly are subject to ACL tears.
A dog's cruciate ligament can rupture suddenly (acute rupture) or slowly tear, getting worse until a complete rupture occurs.
Acute Cranial Cruciate Ligament Ruptures in Dogs
An acute or traumatic cruciate rupture is caused by an injury involving the twisting of the knee joint. This usually happens when a dog incorrectly lands a jump or suddenly turns while running or playing, causing the majority of their weight to be placed onto the twisted knee joint. Cruciate ligament ruptures are usually extremely painful for your pup and will result in sudden lameness of the affected leg.
Some breeds, such as golden retrievers, rottweilers, mastiffs, and labradors are prone to this type of CCL rupture.
Partial Cranial Cruciate Ligament Ruptures in Dogs
Not all cranial cruciate ligament ruptures are acute. Over time, a dog's CCL can slowly stretch and wear down, causing partial tears. This can cause inflammation and pain, but typically does not cause complete lameness. Eventually, the worn-down ligament can completely snap, sometimes with little activity. A dog with partial tears may simply need to hop out of bed for the complete rupture to occur.
Dogs that are older or overweight are more prone to partial cruciate ligament tears.
How are cruciate ligament ruptures in dogs treated?
If you suspect that your dog has an injured CCL it is important to see a vet to have the condition diagnosed and treated.
Complete cranial cruciate ligament ruptures typically require surgery to stabilize the knee, especially if the dog is over ten pounds. Dogs under ten pounds may be able to heal on their own but will require at least six weeks of strict crate rest. Many go on to require surgery eventually anyway.
Surgical treatments for CCL injuries in dogs include:
Extracapsular Lateral Suture Stabilization - ELSS / ECLS
This surgical treatment for a ruptured CCL in dogs works by counteracting 'tibial thrust' (the sliding forward of the dog's tibia) with a specifically placed suture.
Tibial thrust is caused by the transmission of weight up the tibia and across the knee, causing the tibia to “thrust” forward relative to the femur. The forward thrust movement occurs because the top of the tibia is sloped, and the dog's injured CCL which is normally able to oppose the forward force, is no longer able to prevent this unwanted movement.
Extracapsular Lateral Suture Stabilization corrects tibia thrust by “anchoring” the tibia to the femur with a surgically placed suture. The suture pulls the joint tight and helps to stabilize the knee, preventing the front-to-back sliding of the femur and tibia while the CCL heals and the muscles surrounding the knee strengthen.
The suture must stay intact for 8-12 weeks in order for the CCL injury to heal. The suture will then begin to loosen or even break.
This surgery is relatively quick and uncomplicated with a good success rate in smaller dogs. It can also be less expensive than other methods for repairing a torn CCL in dogs. Long-term success varies in dogs of different sizes and activity levels.
Tibial Plateau Leveling Osteotomy - TPLO
Another surgical option for treating your dog's injured CCL is the tibial plateau leveling osteotomy (TPLO). This surgery is more complex than the ELSS and aims to reduce the amount of forward movement during the dog's stride without the help of the CCL.
In this procedure, a complete cut is made through the top of the tibia (tibial plateau). The tibial plateau is then rotated to change its angle and a metal plate is added to stabilize the cut bone as it heals. The tibia will gradually heal and strengthen over the course of several months.
Full recovery from TPLO surgery will take several months however some improvement can be seen within just days of surgery. It is essential to follow your vet's instructions after your dog's TPLO surgery, and restrict your dog's activities in order to allow the bone to heal properly.
The long-term prognosis is good for TPLO treatment in dogs, and re-injury is uncommon. The stabilization plate does not need to be removed from your dog's leg unless it begins to cause problems.
Tibial Tuberosity Advancement - TTA
Tibial Tuberosity Advancement surgery is similar to TPLO but may be slightly less invasive than TPLO. Recovery from TTA appears to be quicker than recovery from TPLO in many dogs.
When TTA surgery is performed the front part of the tibia is cut and separated from the rest of the bone. Next, a special orthopedic spacer is screwed into the space between the two sections of the tibia in order to move the front section forward and up. By doing this, the patellar ligament which runs along the front of the knee is moved into better alignment and helps to prevent much of the abnormal sliding movement. Once this process has been completed, a bone plate will be attached to hold the front section of the tibia in its proper position.
TTA surgery is typically performed in dogs with a steep tibial plateau (angle of the top section of the tibia). Your vet will evaluate your dog's knee geometry to determine which CCL treatment surgery is best for your dog.
How long does it take for dogs to recover from CCL surgery?
On average it will take your dog six to eight weeks to recover following surgery, with good limb function returning within three months. It is very important that you carefully follow your vet's instructions and limit your dog's movement during this period. The activity restriction may be less if a TPLO surgery has been performed.
Unfortunately, even dogs with successful surgery results often will develop arthritis in the affected joint as they age. Weight control and nutritional supplements like glucosamine/chondroitin may help slow the onset of arthritis. Always talk to your vet before giving any supplements to your dog.
Many dogs will receive physical therapy after the surgery to help promote recovery and prevent re-injury.Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.