Cranial Cruciate Ligament (CCL) Tears in Dogs: Treating the Injury

A Common Leg Injury in Dogs
Dog with Brace One of the most common leg injuries experienced by dogs is a cranial cruciate ligament (CCL) tear, similar to an anterior cruciate ligament (ACL) injury in humans. The anterior cruciate ligament is one of the primary ligaments in the knee of human beings.

Where the Cranial Cruciate Ligament (CCL) is Located?
In dogs, the CCL is located in the stifle (knee) joint of the back leg. When the ligament ruptures, joint instability or lameness is typically the result. Left untreated, the injury can lead to joint degeneration or further injury to the connective tissues.

The joint of the stifle is stabilized and supported with four articular ligaments, made up of the medial and lateral collateral ligaments on the outside of the stifle. The caudal and cranial cruciate ligaments located within the stifle itself.

cranial cruciate ligament location

The CCL itself affixes to the femur (the large bone in the thigh), and spans over the stifle joint before it connects to the tibia. The tibia and fibula are bones located in the lower leg, with the tibia being the larger of the two bones.

Between the tibia and femur is the meniscus. The meniscus is a cartilage whose primary function is to absorb the impact created when a dog jumps or runs. If you’ve ever heard of anyone complaining of a torn cartilage, the meniscus represents this fibrous band in humans.

Dogs That are at a Greater Risk for Injury
Again, injury to the CCL is one of the most prevalent orthopedic complaints in veterinarian offices and is the most frequent cause of degeneration of the stifle joint. Larger, overweight canines are more susceptible to a tear of the CCL and the effects are much more severe; compensated pain for the size and weight of the breed. While an injury can occur in all breeds and sizes of dogs, it happens most often in such large breeds as:

The Bullmastiff
The Chow
The German shepherd
The Golden retriever
The Labrador retriever
The Saint Bernard
The Rottweiler

Ruptures Related to Age
With respect to age, CCL ruptures occur most often in dogs aged from five to seven years old, and are brought on by degeneration of the stifle joint. In younger dogs, or those canines under four years of age, injury is the most common reason for the tear. Again, large, younger dogs are much more likely to sustain damage than smaller canine breeds are.

How an Injury Can Develop
An acute rupture or injury can suddenly occur when the ligament is twisted, thereby causing the tissue to hyperextend or over-rotate. For example, if a dog runs and, say, partially steps in a hole, then a tear can result. In older animals, weakened tissues cause the joint to become unstable, resulting in a partial tear. This partial tear subsequently leads to the larger injury.

Therefore, the risk for a CCL tear is greater in dogs that are older, or that are larger or overweight. Dogs that have arthritis or exhibit abnormalities in their gait, such as a luxating patella (floating kneecap) or bowleggedness, are vulnerable to tendon tears as well.

Unfortunately, when the CCL becomes torn or ruptured, only the surrounding tissues and muscles are left to keep the bones of the tibia, fibula, and femur intact. Whether the damage is caused suddenly or by chronic repetitiveness, the tear normally results in hind limb pain or lameness. Not only that, a dog that uses its contralateral (uninjured) leg to compensate for the injury may cause damage to the good leg as well. So, immediate measures should be taken to correct the situation before it gets worse. The prospects for recovery increasingly diminish the longer the problem is left unaddressed.

Planning a Course of Treatment
So, when a CCL tear is diagnosed, a dog should start to receive a course of treatment as soon as possible. That can mean treating the dog with medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), for the pain and placing certain restrictions on activity. The main objective of treating the injury is to alleviate any discomfort, increase the stability and functioning of the stifle joint, and decrease the chance for degenerative damage.

Surgery - The Most Reliable, if Not Effective, Cure
While a conservative treatment approach can be followed initially, surgery is typically the most reliable cure and the ultimate treatment option in most cases. That's because the cruciate ligament, if torn or overstretched, will not heal or reattach unless surgery is performed. Several surgical procedures are currently used to reconstruct or correct a torn CCL, depending on the nature and severity of the injury.

Surgical Options for a CCL Injury

Generally, CCL procedures are designed to change the angle of the stifle joint so a dog can bear weight more easily. The main surgery options include tibial plateau leveling osteotomy (TPLO), tibial tuberosity advancement (TTA) or triple tibial osteotomy (TTO).

TPLO (Tibial Plateau Leveling Osteotomy)
TPLO is a technique that alters the bones in the stifle joint so they are more balanced. The surgeon begins the procedure by making a cut down the span of the leg before removing the damaged ends of the CCL. An incision is then made at the top of the tibia and the bone is measured.

TPLO Surgery:

The flat part or plateau of the top portion of the bone is repositioned to level out the slope of the knee. To keep the altered slope intact, a metal plate is inserted. Generally, dogs can start bearing weight on their leg after a couple weeks. After two months, indications of bone healing are evident and the animal is well on its way to recovery.

TTA (Tibial Tuberosity Advancement)
TTA surgery, or tibial tuberosity advancement, is a technique that involves manipulating the stifle joint to enhance stability. Therefore, the procedure alters the angle of the bone in the stifle joint, or repositions the tibia. In order to facilitate the process, the veterinary surgeon will make a four to six inch incision along the stifle joint to gain entry to the CCL and, in some cases, the meniscal cartilage. The tibia is then cut and positioned forward to be removed after the bone has began healing.

TTA Surgery:

A couple weeks after the procedure, your dog should be using his leg much more regularly. The bone should be healed in its entirety after two months' time.

TTO (Triple Tibial Osteotomy)

Triple Tibial Osteotomy:
Triple Tibial Osteotomy on Dog

A TTO, short, again, for triple tibial osteotomy, is a combination of the techniques used in TPLO and TTA procedures. The procedure involves making an incision into the tibial bone to alter the stifle joint's angle. During the procedure, the veterinary surgeon makes three incisions into the tibia.

The cuts permit the vet to rotate the flat top part of the tibia, known as the plateau, and move the tibial tuberosity (a bony projection on the top part of the tibia) slightly forward. Thereafter, a metal plate is inserted to maintain the new angle for the joint. Full healing takes place after about a month and a half with your dog bearing some weight on the leg after two weeks.

Chondroprotective Agents
Rehabilitation and physical therapy should be incorporated gradually to ensure complete healing and to prevent reinjury. After any surgical procedure, a dog typically is given NSAIDs or other supplements or medications to promote the repair of the cartilage. Supplements used for this purpose are called chondroprotective agents. The agents are available over-the-counter and by prescription and are recommended for keeping joints and cartilages lubricated. The remedies are also beneficial in relieving pain and inflammation. Examples of chondroprotective agents include:

Vitamin C
Hyaluronan
Omega 3 and 6 Fatty Acids
Polysulfated glycosaminoglycans
Chondroitin Sulfate
Glucosamine

Preventative Measures and Recommendations
Dogs that are overweight that suffer from CCL damage often can obtain a good deal of pain relief from losing weight. A regulated exercise program and healthy diet can assist in stimulating cartilage growth in older animals as well. For example, controlled, lengthy walks can help curtail the loss of muscle mass.

The following video further demonstrates the process:

After-surgery Care and Rehabilitation
After-surgery care often includes physical therapy in the form of hydrotherapy (water exercise), or passive flexion and extension of the leg. A dog should stay confined in one area of the house during the recovery period and should only be walked if he needs to go outside at that time.

The following video further demonstrates flexion and extension therapy for the leg:

After-surgery Prognosis
The prognosis for dogs that undergo surgery for tears to the CCL is excellent. By stabilizing the stifle joint through surgical means and following a course of rehabilitation, a dog that was formerly lame can walk again and eventually use the once-injured limb.

Health Problems that Can Develop if Surgery is Not Undertaken
Dog with osteoarthritis Without undergoing surgery, a CCL rupture can cause osteoarthritis, muscle atrophy or injury of the meniscus. Again, the risk of injuring the contralateral limb (good leg) is further increased as that leg must bear the brunt of the load for the injured leg.

Fitting a Dog with a CCL Tear with an Orthopedic Brace: When it is Recommended
However, another option, besides surgery, deserves notice too. Some veterinarians recommend dogs with a CCL injury be fitted with an orthosis or orthopedic brace. The brace is advised as an adjunct to surgery, to support healing after surgery, or as a surgery alternative.

Good Candidates for Orthopedic Braces
Dogs that are advanced in years are often good candidates for orthopedic braces as are dogs that are unable to tolerate anesthesia. The brace is an option too when surgery is unaffordable.

As a temporary measure, orthopedic braces are recommended for dogs in the following circumstances.

Dogs that need surgery which are too young for the repair can benefit from wearing a brace in the interim.
Dogs that have already undergone a procedure and require added support are also good candidates for a brace to help alleviate some of the pressure and pain related to having a CCL procedure or injury.

The Benefits of Orthopedic Braces
Orthopedic braces support injured joints and ligaments by allowing damaged limbs to relax, thereby lessening fatigue and stress. In addition, an orthosis is helpful in reducing swelling and discomfort and increasing a dog's confidence in using his leg.

Besides CCL injuries, braces are used for injuries involving the hock or carpus too. Orthopedic braces made for stifle joints replicate the functioning of a healthy knee and assist in offloading it.

To customize a brace, a cast is made of the injured leg. A break-in period of about a week is necessary for a dog to become accustomed to wearing the device. Whether it is used as a post-surgery form of treatment or worn as an alternative to surgery, it is a proven method of care.

An example of a dog wearing a stifle orthosis is shown in the following video: