FAQs on CCL: Cranial Cruciate Ligament Injuries in Dogs
I frequently speak with pet owners whose dog has a suspected CCL injury. Here are the most common questions these owners have.
What is a CCL (cranial cruciate ligament)?
The cranial cruciate ligament is a ligament inside the knee of dogs that provides stability of the knee when a dog runs and walks. This ligament is very similar to the anterior cruciate ligament (known as the ACL) in people. These ligaments in dogs and people have nearly identical anatomy but different names because dogs walk on four limbs and people on two. CCL ligaments are only found in dogs’ back legs.
How is an injury to this ligament diagnosed?
In most cases, dogs present to the veterinary clinic with a back leg lameness or limp. Veterinarians will examine the dog, trying to isolate the source of pain. Veterinarians use two techniques to test the stability of the knee: cranial tibial thrust and cranial drawer. If there is thrust and/or drawer present in a dog’s knee, this indicates there is a CCL injury. X-rays are often recommended to help rule out any other causes of pain or lameness, but the ligament itself cannot be seen on x-rays. There are some x-ray findings that make veterinarians suspicious of underlying CCL injury, but true diagnosis is made from physical exam and laxity in the knee joint.
How did this rupture happen?
In dogs, cranial cruciate ligament injury and/or rupture is thought to be due to degeneration of the ligament over time. Unlike people, where a traumatic injury – often sports-related – causes ACL injuries, in dogs the cause is usually degeneration, which leads to injury or even rupture through normal activity. Although a traumatic injury can cause a CCL rupture in dogs, it is less common.
What can we do to help our dog feel better?
When a dog experiences a CCL injury, anti-inflammatory pain medications and rest are recommended. Human pain medications are not safe for dogs, so be sure to consult your veterinarian to discuss appropriate medications for your dog. In addition to rest and medications, surgery is the gold standard for treatment of a CCL injury. Various surgical techniques are available, and your veterinarian will discuss the best option for your dog.
How much does surgery cost?
I recommend that owners see a board-certified surgeon for their pet’s orthopedic surgery. These veterinarians have had additional training to specialize in advanced surgical techniques. As previously mentioned, there are multiple different surgical stabilization techniques for CCL injuries. The most-performed technique in the Chicago area is the Tibial Plateau Leveling Osteotomy (TPLO). These procedures cost between $4,000 to $6,000 in Chicagoland.
Can we use a brace like in humans?
Unfortunately, braces and/or wraps are typically not beneficial in dogs. This is because dogs walk on their tiptoes, so their knee is always bent. (Try it: If you stand on your tiptoes, your knee will be bent too). We humans walk flat-footed, so our weight can transfer from our hip to heel. Since this weight transfer cannot occur in dogs, braces are ineffective.
What if surgery is not an option?
In many cases, surgery is not financially feasible, or it may not be in the best interest of the dog due to other underlying health issues. In these cases, I recommend multi-modal therapy. This includes strict rest for 4 to 8 weeks, long-term non-steroidal anti-inflammatories (NSAIDs), high-quality omega-3 supplements, and glucosamine/chondroitin supplements, along with weight loss. After the period of rest, physical therapy can be very beneficial as well.
With time, the knee will stabilize, but with the stabilization comes more arthritis formation. The body develops arthritis to try to stabilize the knee joint. Surgery on the knee reduces instability, so the body does not form as much arthritis in that joint. However, even with arthritis, dogs are able to compensate well. Many dogs do well without surgery, although the injured leg may always cause some discomfort. The dogs that typically do not do well without surgery are very large dogs that already have joint disease, such as advanced hip dysplasia.
One exception to the surgery rule is toy breed dogs and cats. We do not commonly see CCL injuries in these pets, but when we do, they typically do really well with cage rest and medications and surgery is not often needed.
What about the other leg?
Unfortunately, over 50% of dogs will rupture their other CCL within a year of the first rupture. This can be explained by the fact that both ligaments are typically degenerating at a similar rate. I like to always warn owners of this because they may be faced with the decision to pursue surgery again soon.
How can we prevent a CCL injury?
Unfortunately, there seems to be a hereditary component. We do not have a good method of determining which dogs that will have CCL injuries in their life. However, maintaining an ideal weight is key to joint health. I would also recommend considering pet insurance prior to any issues. Insurance does not cover pre-existing conditions, so don’t wait until your pet starts limping. I have seen CCL injuries in dogs as young as 6 months old, but most commonly we see them in medium to large breed, active, overweight dogs aged 2 to 6 years old.
Dr. Drew Sullivan