Cranial Cruciate Ligament Injuries in Dogs: What You Need to Know
When we think of cruciate ligament tears, it’s usually in association with pro athletes or weekend warriors — but our dogs can suffer cranial cruciate ligament (CCL) injuries as well. In fact, it’s the most common orthopedic problem that we veterinarians see.
Remember that old song Dry Bones, about how “the shin bone's connected to the knee bone”? Well, the cranial cruciate ligament is one of the ligaments that connects the thighbone to the shinbone where they meet at the knee (known as the stifle joint in dogs) and helps hold the joint stable. Basically, it functions like a rope, preventing the stifle bones from shifting abnormally during activity.
What Causes CCL Disease
When the CCL becomes injured — which can happen suddenly or over a long period — it’s not only painful in the instant it happens, it also leads to painful degenerative joint disease if it’s not repaired. Dogs typically suffer CCL tears (also known as CCL disease) for three major reasons:
- They are overweight.
- They are out of condition and then are asked to perform athletic feats that are beyond their abilities (weekend warrior syndrome).
- They jump, twist, turn or land wrong (on slippery surfaces, for instance).
Dogs are also more prone to CCL tears if they’ve had a previous CCL injury on the opposite leg. A body slam during rough play can leave a dog sitting on the sidelines howling. And CCL tears can result from long-term chronic degeneration.
We don’t know yet if there is a genetic component to CCL ruptures. Any breed or mix can suffer one, but this type of injury is most often seen in young Labrador Retrievers and Rottweilers (less than 4 years old), dogs older than 5 years, and young large-breed dogs. Other breeds that seem to have a disproportionate number of CCL injuries include Bernese Mountain Dogs, Mastiffs, German Shepherd Dogs, Golden Retrievers and Saint Bernards. Spayed females are also susceptible to these injuries.
Signs of CCL Rupture
You may or may not see the actual injury occur. If you do, the first sign will likely be a loud yelp of pain from your dog.
The most obvious clue that your dog may have suffered a CCL injury is lameness or reluctance to put weight on a rear leg. Your dog may hold his limb up or use the leg intermittently. Some dogs display what we call a lazy sit, holding the affected leg out to the side. You may notice that the stifle joint is swollen or that it makes a clicking sound when your dog walks, which may indicate meniscal injury. In many instances, the injury may have been building up for some time. A CCL tear, or rupture, can be partial or complete.
Any time your dog appears to be lame, he needs to be seen by a veterinarian. To diagnose the problem and rule out other causes of lameness, your veterinarian may manipulate the leg to check the stifle’s range of motion, remove fluid from the stifle joint (a procedure known as arthrocentesis) to check for the presence of inflammatory cells, microorganisms or immune-mediated diseases that could be causing the problem, and examine the knee joint arthroscopically to get a look at the ligaments and cartilage. Radiographs (x-rays) or an MRI can also help to confirm a diagnosis.
What we want to do for dogs with CCL injuries is to relieve pain, improve function and put the brakes on the advancement of osteoarthritis. How CCL disease is treated depends on several factors. Smaller dogs may get by with rest, physical rehab sessions, and medication for pain. Larger dogs or performance dogs, such as field trial champions or agility stars, are more likely to need surgery, especially if the goal is for them to return to their former activities.
Other factors to consider include the dog’s age and activity level, not to mention your budget. The cost of surgery can go as high as $6,000, so that’s certainly an important component of your decision. Your veterinarian may also have a preference based on experience and training in orthopedic surgery. There’s no single right answer, so don’t hesitate to discuss all the options.
And we have a lot of options when it comes to surgical repair. They include the TightRope (TR) stabilizing procedure; a lateral suture (LS) procedure; a tibial plateau leveling osteotomy (TPLO); and a tibial tuberosity advancement (TTA) procedure. The TPLO and the TTA involve cutting the bone to rebuild the knee, while the TR and LS are less invasive implants that use synthetic materials to bind the femur and tibia. Each procedure has pros and cons. Ask about their complication rates and long-term success rates.
In the future, we may be able to use regenerative therapies to repair CCL injuries. Researchers are looking at whether platelets from a dog’s own blood, which contain growth factors, can heal the injuries. Another area of research is the use of stem cells to rebuild the tissue.
In the meantime, take the following steps to help prevent CCL disease in your dog:
- Keep him lean. I can’t stress this enough. Fat dogs are at increased risk for developing CCL injuries.
- Keep him active. Dogs need daily exercise for good muscle tone and joint health.
- Keep him safe. Provide a ramp to help your dog get in and out of the car, and don't let him jump or run on slick surfaces.
Reconsider the age at which you spay or neuter your dog. It may be better to wait until the dog reaches full skeletal maturity or — for males — to use the Zeutering procedure, which sterilizes the dog but maintains a higher level of testosterone, which can have a protective effect on joints.
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