What is the ACL, CCL or Cruciate?
In a person's knee there is a thin piece of connective tissue called the anterior cruciate ligament (ACL) connecting our lower leg bone (tibia) to our upper leg bone (femur) and helping our knee function efficiently. You dog also has connective tissue joining their tibia and femur however, in dogs this tissue is called the cranial cruciate ligament or CCL.
Although the dog's CCL and the person's ACL function somewhat differently, pet owners and vets will often refer to the dog's cranial cruciate ligament as the dog's ACL, CCL or 'cruciate' interchangeably.
How did my dog's ACL become injured?
ACL injuries in dogs typically come on gradually rather than suddenly, and become progressively worse with activity. For many dogs there is no defining moment when their ACL injury suddenly occurred, instead it is more likely that through continued exercise, symptoms which began as mild gradually became more pronounced and painful for your dog.
What are the signs of ACL injuries in dogs?
A dog that is suffering from a torn ACL will not be able to walk normally and will experience significant pain. If your dog has torn their ACL you may notice that they are limping in their hind legs, showing signs of stiffness following exercise, and having difficulties jumping or rising up off of the floor.
What happens when a dog's ACL is torn or injured?
When a dog's ACL has been injured, the tibia slides forward in relation to the femur. This forward sliding movement is known as a 'positive drawer sign' and results in knee instability which can lead to osteoarthritis or damage to the cartilage and surrounding bones.
What treatments are available for a torn ACL in dogs?
If your dog is showing signs of an ACL injury it's important to see a vet to have the condition diagnosed so that treatment can begin before symptoms become more severe. Many dog's with a single ACL injury will often go on to injury the other leg soon afterwards.
Surgery Options for Treating ACL Injuries in Dogs
Extracapsular Lateral Suture Stabilization - ELSS / ECLS
This surgical treatment works by counteracting the sliding forward of the dog's shinbone ('tibial thrust') with a specifically placed suture.
The sliding motion of tibial thrust is caused by the transmission of weight up the dog's tibia and across the knee, causing the tibia to “thrust” forward in relation to the dog's femur (thigh bone). This forward thrust movement occurs because the top of the tibia is sloped, and the dog's injured ACL which would normally able to oppose the forward force, is no longer able to prevent the unwanted movement from occurring.
Extracapsular Lateral Suture Stabilization corrects tibia thrust by “anchoring” the tibia to the femur with suture placed by your dog's surgeon. The suture stabilizes the dog's knee by pulling the joint tight and preventing the front-to-back sliding of the tibia so that the ACL has an opportunity to heal itself, and the muscles surrounding the knee have a chance to regain their strength.
ELSS surgery is fairly quick and uncomplicated with a good success rate in small to medium sized dogs. ELSS surgery can also be less expensive than other ACL surgical treatment options. Long-term success of ELSS surgery varies in dogs of different sizes and activity levels. Speak to your vet to find out if ELSS surgery is an option for your injured dog.
Tibial Plateau Leveling Osteotomy - TPLO
The next surgical option we'll look at for treating your dog's injured ACL is the tibial plateau leveling osteotomy (TPLO). This surgery is more complicated than ELSS surgery and aims to reduce tibial thrust without relying on the dog's ACL (CCL).
This surgery involves making a complete cut through the top of the tibia (tibial plateau), then rotating the tibial plateau in order to change its angle. Finally a metal plate is added to stabilize the cut bone as it heals. Over the course of several months, your dog's leg will gradually heal and strengthen.
Full recovery from TPLO surgery in dogs takes several months however some improvement can be seen within just days of the procedure. Following your vet's post-surgery instructions and restricting your dog's activities, are essential for successful healing. TPLO surgery in dogs has a good long-term prognosis, and re-injury is uncommon.
How long will it take for my dog to recover from ACL surgery?
Some dogs recover more quickly than others following ACL surgery however, recovery from a torn ACL is always a long process!
Many dogs are able to walk as soon as 24 hours after surgery, but a full recovery and a return to normal activities will take 12 - 16 weeks or possibly longer.
It is essential to follow your vet's instructions and pay attention to your dog's healing progress. It's important not to rush exercise following ACL surgery. Never force your dog to do exercises if they resist as this can lead to re-injuring the leg.