The dog's cranial cruciate ligament (CCL) is often referred to as the dog's ACL or 'cruciate'. This connective tissue that joins the upper and lower leg bones at the dog's knee is commonly injured in dogs. Today, our Wake Forest vets describe the types of ACL surgery for dogs.
ACL, CCL or Cruciate - What is it?
In the human knee, there is a thin piece of connective tissue called the anterior cruciate ligament (ACL) which connects the lower leg bone (tibia) to the upper leg bone (femur) and helps the knee maintain proper function. Dogs also have this connective tissue joining their tibia and femur however, in dogs it's called the cranial cruciate ligament (CCL).
Despite the fact that a human ACL and a dog's CCL function somewhat differently, pet owners and vets will often refer to the dog's cranial cruciate ligament as ACL, CCL or 'cruciate' interchangeably.
How did my dog hurt their ACL?
The onset of dog ACL injuries is typically gradual, and become progressively worse with activity. You may never know when your dog has begun to develop an ACL injury, but through continual exercise, symptoms will begin mild but gradually become more noticeable and painful for your dog.
What are the signs that my dog has injured their ACL?
Dogs with an ACL injury cannot walk normally and experience pain. If your dog has injured their ACL you will start to notice limping originating in their hind legs, experiencing stiffness following exercise, and will likely have difficulties standing up off of the floor or jumping.
How are ACL injuries in dogs treated?
If you suspect that your dog has an injured ACL it is important to see a vet and have the condition diagnosed and treated quickly. If left untreated, it can not only cause your dog a great deal of pain but it can also cause injury in the other back leg due to overcompensating for the injury.
If your dog's ACL is torn or injured, the tibia (lower leg bone) slides forward in relation to the femur (thigh bone). This movement is known as a 'positive drawer sign' results in knee instability which could cause to damage to the cartilage and surrounding bones, or possibly lead to osteoarthritis.
Surgical treatments for ACL injuries in dogs include:
Extracapsular Lateral Suture Stabilization - ELSS / ECLS
This surgical treatment for a torn ACL in dogs works by counteracting 'tibial thrust' (the sliding forward of the dog's tibia) with a 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 ACL which normally opposes the forward force, is no longer able to prevent this incorrect 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 ACL heals and the muscles surrounding the knee strengthen.
The suture must stay intact for 8-12 weeks in order for the ACL injury to heal. The suture will then begin to loosen or even break.
This surgery is relatively short and straightforward with a good success rate in smaller dogs. It can also be less expensive than other methods for repairing a torn ACL in dogs. Long-term success varies in dogs of different sizes and activity levels.
Tibial Plateau Leveling Osteotomy - TPLO
Another surgical option for repairing your dog's injured ACL 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 ACL (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 it's angle and a metal plate is added to stabilize the cut bone as it heals. The tibia will start to heal and strengthen over the next couple of 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 bond to heal properly.
The long-term prognosis is good for TPLO treatment in dogs, and the likelihood of re-injury is slim. 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 dogs's knee geometry to determine which ACL treatment surgery is best for your dog.
How long does it take for dogs to recover from ACL surgery?
Recovery can vary from dog to dog and some will recover quicker than others following ACL surgery. This being said the recovery time for ACL surgery for your dog is going to be a long process.
Your dog may be able to walk as soon as 24 hours following surgery, however full recovery and a return to normal activities will take 12 - 16 weeks or maybe longer.
It is essential to follow your vet's instructions and to pay attention to your dog's healing progress. Never force your dog to do exercises if they resist as this can lead to re-injuring the leg.