Cranial Cruciate Ligament Injury

One of the most common conditions we treat here at Walking Paws is a cranial cruciate ligament injury. If your pet has a cranial cruciate injury, it can be difficult to understand all your options and know what’s best for your pet. This article will help you navigate through the process that way you can make an informed decision.

What is a CCL Tear?

Let’s start with the basics. The cranial cruciate ligament (CCL) is a structure inside the knee joint that helps provide stability. The image below gives you an idea of what this ligament looks like.

When the ligament is intact, it helps prevent the bottom bone, the tibia, from sliding forward in relation to the top bone, the femur. However, when it becomes damaged we lose some of that stability and the tibia will shift forward against the femur every time your pet puts weight on their leg. The image below depicts this abnormal movement.

The Progression of CCL Tears

Unlike humans, CCL injuries in dogs are degenerative in the large majority of cases. This means that the ligament slowly breaks down over time due to many factors including the mechanics of the joint, the angle of the top of the tibia, genetics, confirmation, or obesity. We can have different degrees of tears ranging from a very mild tear of just a few fibers, all the way to a complete tear of the ligament. It is not uncommon to have an event that causes the injury to progress from a partial tear to a full tear, resulting in acute limping and pain. Dogs who tear one CCL have a 50% chance of tearing the other CCL in the opposite leg within a year. 

We can also see meniscus injuries occur along with CCL tears. The meniscus is a piece of cartilage that provides cushioning to the knee joint. The knee joint has 2 menisci. The medial meniscus is most commonly injured with a CCL tear and it can become frayed or have a torn flap that sticks up into the joint. A meniscus that is flapping back and forth can be very painful and cause a click to be heard at the knee with movement. A meniscus injury may be suspected based on physical exam, but a definitive diagnosis can only be made with advanced imaging or scoping the joint. The image below depicts an injured medial meniscus.

How is a CCL Tear Diagnosed?

CCL tears are best diagnosed with a combination of physical exam and radiographs to look for changes associated with CCL tears such as swelling, arthritic changes, and a forward shifted tibia. 

When there is injury to the CCL and/or meniscus, there is abnormal mechanics at the joint that leads to inflammation and bony changes. This means that any dog with a CCL tear will likely develop osteoarthritis in their stifle joint.

So what can we do to help our pet’s dealing with a CCL tear? 

Our goals of physical therapy for a CCL tear are to decrease pain, decrease swelling, relax muscles, improve weight bearing, and to rebuild the stabilizers of the knee. By rebuilding the stabilizers of the knee and building up scar tissue, we are no longer dependent on the cruciate ligament for stability. 

With physical therapy, we start with decreasing pain and swelling associated with a CCL tear. We progress into relaxing taut muscles, such as the hip flexors that have been compensating. We utilize stretches and range of motion to improve posture and position of the injured leg. After pain, swelling, and taut muscles are well controlled we then strength build the stabilizers of the knee through hydrotherapy and land based exercises.

Our protocol varies based on our exam findings, the patient, your goals, and the extent of injury.

There are several options we will outline below based on the extent of injury:

1. Partial CCL Tear

Catching a CCL injury at a partial tear offers the best prognosis and is the best time to address the injury. These patients may have a history of limping on the leg, but then a few days later get better. The incidents continue to happen infrequently until one day, they don’t get better and they are at a full CCL tear. So if you can address your dog’s injury at a partial tear, then you have a good chance of preventing further injuries. 

Often we can heal partial CCL tears successfully with physical therapy alone. At times we may place a brace on the leg to stabilize the knee allowing us to strength build the stabilizers around the knee safely. The brace offers us peace of mind that the partial CCL tear is at lower risk of pushing into a full tear or worse concurrent meniscus tear. When we get to a point where the patient’s knee is stable on exam and the muscles are firing quickly and strong enough, we start working the patient out of the brace. We have had a great amount of success healing partial CCL tears with physical therapy and bracing.

2. Full CCL Tear

When a dog acquires a full CCL tear, we prefer for the knee to be stabilized. We often recommend stabilization through bracing or surgery, followed by physical therapy. We have had great success stabilizing knees with a brace in combination with physical therapy. The process is longer than a partial CCL tear to get to the point of stability. We have had many patients with full CCL tears in a brace and physical therapy get back to running and hiking again. We have also had great success of patients who received a TPLO or CBLO followed by physical therapy get back to previous activity. At our first appointment, we can consult with you on the likelihood of success for your pet with each route.

3. CCL tear with a Meniscus Tear

When we are suspicious of a meniscal tear, we often recommend surgery. If surgery is not an option, we pursue rehabilitation and bracing with the goal of focusing on pain management heavily. Braces can stabilize the knee to prevent a shifting motion, but they can not alleviate the pain originating from the meniscus. So we focus on pain management through medications and our different therapies offered at Walking Paws Rehab. If the meniscus is not removed, we aim at trying to get the meniscus to scar down. We have had success with patients with full CCL tear and meniscal tears get back to a point of no limping and hiking/running again by going the bracing and physical therapy route. The progression is slower and the prognosis is unknown though.

Another option is to pursue surgery to stabilize the knee and remove the meniscus. If surgery is pursued, our physical therapy is then focused on improving healing from the fracture created through a TPLO or CBLO procedure and getting the patient back to weight bearing and full function.

Another option that isn’t pursued frequently is arthroscopy to remove the injured meniscus and ligament to relieve pain followed by a brace to stabilize the knee and physical therapy. This option is not chosen too often given that it is the most expensive option.

Ultimately, if your dog has acquired an injury to the cranial cruciate ligament, you have come to the right place for help. Cranial cruciate tears are the most common injury we see at Walking Paws Rehab. We have successfully rehabbed patients who went the physical therapy alone route, who have selected bracing with physical therapy, or who have opted for surgery with post operative rehabilitation. At our initial appointment, we can help you decide which route is best for your loved one and get started on a plan towards healing!

References:

  1. Bockstahler, B., & Wittek, K. (Eds.). (2019). Essential Facts of Physical Medicine, Rehabilitation and Sports Medicine in Companion Animals. Babenhausen: VBS VetVerlag.

  2. Millis, D. L., & Levine, D. (2014). Canine rehabilitation and physical therapy. St. Louis: Saunders.

  3. Zink, C., & B., V. D. (2018). Canine sports medicine and rehabilitation. Hoboken, NJ: Wiley Blackwell.

  4. Cohn, L. A., &; Côté, E. (2020). Côté’s clinical veterinary advisor. St. Louis, MO: Elsevier.

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