What is a CCL Tear?
The cranial cruciate ligament (CCL) is an important ligament in the knee, also known as the stifle joint. The CCL attaches to the thigh bone (femur), runs across the knee, and then attaches to the shin bone (tibia). It holds the tibia in place, preventing hyperextension and internal rotation. The cartilage located between the femur and the tibia, called the meniscus, is responsible for absorbing impact.
This same ligament is called the anterior cruciate ligament (ACL) in humans. When the CCL is ruptured, it means the ligament suffers a tear. This causes partial or complete joint instability, lameness, and pain. Your dog may limp or may not be able to use the leg at all. When there is a CCL rupture, the meniscus can be torn due to the knee’s instability then.
Here’s the big problem: torn ligaments can retract, causing them not to heal completely. So, if the injury remains untreated, it may lead to degenerative joint disease and permanent damage to the connective tissues in the knee. What this means is that they can cause permanent lameness in your dog’s leg if not treated and leaves them at higher risk for injuring the other leg due to compensating for the injury. CCL ruptures are very painful and unfortunately, it’s a common and serious injury.
What Dogs Are at Risk for a CCL Rupture?
CCL ruptures are one of the most commonly-seen orthopedic injuries in dogs and they are the most common cause of degenerative joint disease in the knee. Any dog may be at risk for this type of injury. They happen to dogs of all sizes, though they tend to be most prevalent in large and giant breed dogs. Activity, breed, obesity, and age are all factors that may increase a dog’s risk of this type of injury.
Though CCL injuries in dogs often occur due to overexertion during certain kinds of high-impact activities, this may not always be the case. Some dogs are just prone to this and can tear their CCL doing something as minimal as jumping off the bed. Others may have this injury who are more athletic.
Another fairly common knee issue is called patellar luxation. This is a congenital knee condition that is more common in small dogs where the kneecap rides outside of the femoral groove when the knee is flexed. In “layman’s terms,” people refer to this as the kneecap popping out. It is important to recognize that if your dog has a luxating patella, it increases your dog’s risk of a CCL injury too.
Sign of a CCL Rupture and What to do if You Suspect One
The severity of the CCL injury will impact the dog’s clinical signs. You might see a range from a slight limp to the dog being entirely unable to bear weight on the injured leg. You might also see swelling around the inside of the knee. Your dog may favor one leg or have difficulty lying down or getting up. You might also notice your dog react to pain or tenderness near the injured knee when you touch him.
If you suspect your dog may have a CCL tear, you should call your vet to schedule an exam as soon as possible to avoid further damage and put your dog on crate rest. The vet can do a physical exam to identify this type of injury by testing for the presence of what’s called the “drawer sign.” When the vet holds the dog’s thighbone in place, if there is a CCL tear, the shinbone can be pulled forward, similar to a drawer sliding open.
A vet may also take x-rays to investigate the extent of the damage and to determine if there may be other issues like arthritis, bone fragments, and the presence of fluid in the joint.
Treatment Options of a CCL Injury
Though most people expect surgery will be required for a CCL tear, that’s not always the case. It depends on a number of things including your dog’s overall condition, activity level, and the extent of the injury.
There are four common surgical options used to correct a CCL rupture in dogs including:
- Arthroscopy — For partial CCL tears and meniscus tears with very minimal damage, they may be repairable through arthroscopy. It’s a technique that is minimally invasive and can be effective with very minor tears.
- Tibial Plateau Leveling Osteotomy (TPLO) — This surgery entails cutting and leveling the tibial plateau. Then the surgeon stabilizes it using a plate and screws, eliminating the need for the ligament by changing the angle of the knee when your dog is bearing weight on it. It’s an expensive surgery often used for larger breeds and active dogs.
- Extracapsular or lateral suture — This technique stabilizes the knee using sutures placed on the outside of the knee joint. It’s commonly used for small-to-medium-sized dogs that are 50 pounds or less and typically less active dogs.
- Tibial Tuberosity Advancement (TTA) — This surgery cuts the top of the tibia, moves it forward and stabilizes it using a plate. It replaces the function of the CCL instead of repairing it.
In some cases, physical rehabilitation may be a helpful and appropriate course of treatment. In my practice, I have rehabbed many dogs with CCL ruptures. The ligament cannot grow back together—think of it as a fraying in a rope. However, a dog’s body can build up scar tissue that stabilizes the joint so he can return to normal activity over time.
The treatment varies based on the dog’s injury and condition, but it generally includes restricted activity, anti-inflammatories, cold-laser therapy, and the use of an Assisi loop (which you do at home). We start slowly with very short walks and work up to exercises to strengthen the muscles, other ligaments, and tendons around the knee, much of which you do at home.
It’s a long and slow process requiring consistent work and vigilance to ensure the dog doesn’t do anything to further the injury. However, for the right dog (and family), it may be a great option worth considering to avoid costly surgery or if surgery is not an option. If you think your dog may have a CCL rupture, schedule an appointment with your primary vet or rehab vet.