Cruciate Ligament Injuries in Dogs and How to Treat Them
At Evergreen Animal Clinic we diagnose over 100 cases of Cranial Cruciate Ligament (CCL) tears each year, making it the most common orthopedic injury in dogs. Cats can also experience CCL tears, but they are far more widespread among dogs.
The CCL is the dog equivalent to the Anterior Cruciate Ligament (ACL) in human knees. CCLs connect the back of the femur with the front of the tibia, stabilizing dogs’ knee joints by preventing them from overextending or twisting.
Ligament damage can occur from an acute tear from excessive strain, a traumatic avulsion, or a progressive degenerative disease. If your dog is limping on its hind leg, has swelling on the inside of a knee, or refuses to walk on an injured leg, a ruptured or torn CCL may be to blame.
The CCL is the dog equivalent to the Anterior Cruciate Ligament (ACL) in human knees. CCLs connect the back of the femur with the front of the tibia, stabilizing dogs’ knee joints by preventing them from overextending or twisting.
Ligament damage can occur from an acute tear from excessive strain, a traumatic avulsion, or a progressive degenerative disease. If your dog is limping on its hind leg, has swelling on the inside of a knee, or refuses to walk on an injured leg, a ruptured or torn CCL may be to blame.
Common Causes of Ligament Tears
Cruciate ligament injuries are caused by a variety of factors, including age, activity, obesity and genetics (i.e., breed).
Age: As dogs age, their cruciate ligaments can degenerate, creating weak or unstable joints. Arthritis and other degenerative diseases can also cause deterioration of the joint, making it more prone to CCL tears.
Activity: Whether it’s a sudden injury from jumping or turning sharply, or a repetitive-use injury from participation in field trials or agility courses, cranial cruciate ligament tears can happen in even the healthiest of dogs. And, like their human counterparts, sedentary dogs that become “weekend warriors” (e.g., a full day of frisbee) are at higher risk of injury.
Obesity: Dogs’ knees are always in a bent position, putting a constant load on their CCLs. Extra weight adds even more stress to dogs’ joints, making them more susceptible to injury. Weight loss is recommended as a preventive measure.
Breed: Certain breeds are more prone to orthopedic issues, particularly larger breeds that experience hip dysplasia and compensate by placing weight elsewhere on their bodies. Breeds that more commonly experience cruciate ligament problems include:
Cruciate ligament injuries are caused by a variety of factors, including age, activity, obesity and genetics (i.e., breed).
Age: As dogs age, their cruciate ligaments can degenerate, creating weak or unstable joints. Arthritis and other degenerative diseases can also cause deterioration of the joint, making it more prone to CCL tears.
Activity: Whether it’s a sudden injury from jumping or turning sharply, or a repetitive-use injury from participation in field trials or agility courses, cranial cruciate ligament tears can happen in even the healthiest of dogs. And, like their human counterparts, sedentary dogs that become “weekend warriors” (e.g., a full day of frisbee) are at higher risk of injury.
Obesity: Dogs’ knees are always in a bent position, putting a constant load on their CCLs. Extra weight adds even more stress to dogs’ joints, making them more susceptible to injury. Weight loss is recommended as a preventive measure.
Breed: Certain breeds are more prone to orthopedic issues, particularly larger breeds that experience hip dysplasia and compensate by placing weight elsewhere on their bodies. Breeds that more commonly experience cruciate ligament problems include:
- Newfoundlands
- Neapolitan Mastiffs
- Akitas
- Saint Bernards
- Rottweilers
- Chesapeake Bay Retrievers
- American Staffordshire Terriers
- Labrador Retrievers
- Golden Retrievers
- Other popular large breeds
DIAGNOSIS
CCL tears are diagnosed through direct physical examination, a review of the dog’s medical history, and x-rays or other diagnostic tools. In some cases, when dogs are in a lot of pain, they may be sedated during the orthopedic examination.
During the exam, the veterinarian will perform certain diagnostic tests, including the cranial “drawer test” in which the vet holds the dog’s femur in place while pushing the tibia forward (much like sliding a drawer). They will also look for signs of stifle joint effusion (e.g., synovial fluid) and medial buttress, palpate the knee joint, perform a tibial compression test, and search for indications of meniscal injuries. A radiograph (x-ray) of the knee is an important part of the diagnosis. It cannot directly implicate the cranial cruciate ligament as the source of the pet’s lameness, but it can help rule out other significant causes of lameness such as infections and cancer.
TREATMENT
Without treatment, the symptoms from a torn or ruptured CCL may somewhat improve on their own within six to twelve weeks, especially with small dogs. However, the absence of a healthy, functioning CCL will likely cause other problems over time, including pain, arthritis, and a decreased range of motion.
To determine the best course of action, the veterinarian will consider the severity and duration of the injury, as well as your dog’s age, size, and overall condition (e.g., is the dog overweight). Cruciate ligament tears can be treated through surgical or non-surgical means, depending on the circumstances.
NON-SURGICAL MANAGEMENT
Surgery is usually recommended for all dogs. However, small dogs, usually less than 30 pounds, can sometimes do well without surgery, using a combination of rest, anti-inflammatory medications, nutraceuticals (i.e., foods and nutritional supplements), physical therapy, and weight loss (for obese dogs). In general, surgery is recommended for all dogs larger than about 30 pounds.
SURGICAL MANAGEMENT
Left untreated, CCL tears often lead to further problems in the affected knee. In addition, when one CCL is ruptured, a dog will transfer its weight to the other leg, increasing the likelihood of CCL overuse in the second leg. Dogs with tears in both CCLs will have difficulty getting up, walking, and defecating.
Early surgical intervention in dogs with CCL tears helps in preserving the remaining intact ligament, leading to better long-term outcomes. There are a variety of surgical techniques, all of which strive to provide stability to the joint.
In 2018, the Journal of the American Veterinary Medical Association (JAVMA) published a study in which members of the Veterinary Orthopedic Society reported their preferred methods of surgical repair. Their preferences were as follows:
Each surgical option has risks and benefits, so a consultation with a surgeon is appropriate to determine which option is best for each pet.
PROGNOSIS
Most dogs recover well after a CCL injury if it is managed appropriately, returning to activities they previously enjoyed. However, because the underlying causes of the injury remain (e.g., arthritis, genetics), an estimated 50% of dogs will experience a CCL tear in the opposite knee within two years. For this reason, it’s a good idea to examine both knees during the evaluation and work on implementing measures to prevent or slow the progression of problems, for example, through weight management or better nutrition.
If you think your pet might be suffering from a cruciate ligament tear, please contact us to schedule an evaluation.
CCL tears are diagnosed through direct physical examination, a review of the dog’s medical history, and x-rays or other diagnostic tools. In some cases, when dogs are in a lot of pain, they may be sedated during the orthopedic examination.
During the exam, the veterinarian will perform certain diagnostic tests, including the cranial “drawer test” in which the vet holds the dog’s femur in place while pushing the tibia forward (much like sliding a drawer). They will also look for signs of stifle joint effusion (e.g., synovial fluid) and medial buttress, palpate the knee joint, perform a tibial compression test, and search for indications of meniscal injuries. A radiograph (x-ray) of the knee is an important part of the diagnosis. It cannot directly implicate the cranial cruciate ligament as the source of the pet’s lameness, but it can help rule out other significant causes of lameness such as infections and cancer.
TREATMENT
Without treatment, the symptoms from a torn or ruptured CCL may somewhat improve on their own within six to twelve weeks, especially with small dogs. However, the absence of a healthy, functioning CCL will likely cause other problems over time, including pain, arthritis, and a decreased range of motion.
To determine the best course of action, the veterinarian will consider the severity and duration of the injury, as well as your dog’s age, size, and overall condition (e.g., is the dog overweight). Cruciate ligament tears can be treated through surgical or non-surgical means, depending on the circumstances.
NON-SURGICAL MANAGEMENT
Surgery is usually recommended for all dogs. However, small dogs, usually less than 30 pounds, can sometimes do well without surgery, using a combination of rest, anti-inflammatory medications, nutraceuticals (i.e., foods and nutritional supplements), physical therapy, and weight loss (for obese dogs). In general, surgery is recommended for all dogs larger than about 30 pounds.
SURGICAL MANAGEMENT
Left untreated, CCL tears often lead to further problems in the affected knee. In addition, when one CCL is ruptured, a dog will transfer its weight to the other leg, increasing the likelihood of CCL overuse in the second leg. Dogs with tears in both CCLs will have difficulty getting up, walking, and defecating.
Early surgical intervention in dogs with CCL tears helps in preserving the remaining intact ligament, leading to better long-term outcomes. There are a variety of surgical techniques, all of which strive to provide stability to the joint.
In 2018, the Journal of the American Veterinary Medical Association (JAVMA) published a study in which members of the Veterinary Orthopedic Society reported their preferred methods of surgical repair. Their preferences were as follows:
- Tibial Plateau Leveling Osteotomy (TPLO) (78.6%)
- Tibial Tuberosity Advancement (TTA) (13.9%)
- Lateral Fabellotibial Suture (LFS) (5.9%)
- Tightrope (TR) (1.6%)
Each surgical option has risks and benefits, so a consultation with a surgeon is appropriate to determine which option is best for each pet.
PROGNOSIS
Most dogs recover well after a CCL injury if it is managed appropriately, returning to activities they previously enjoyed. However, because the underlying causes of the injury remain (e.g., arthritis, genetics), an estimated 50% of dogs will experience a CCL tear in the opposite knee within two years. For this reason, it’s a good idea to examine both knees during the evaluation and work on implementing measures to prevent or slow the progression of problems, for example, through weight management or better nutrition.
If you think your pet might be suffering from a cruciate ligament tear, please contact us to schedule an evaluation.
