Professional –– or weekend –– human athletes know all about the debilitating pain of knee injuries. We’ve all heard about someone going on the disabled list because of an ACL injury. Unfortunately, some dogs have to deal with this kind of knee trouble as well. A cruciate ligament injury in dogs causes pain and lameness and may come on suddenly due to an injury or very gradually due to ligament degeneration. Any dog can suffer a cruciate ligament injury. Medications for pain and inflammation, as well as joint supplements can help in some cases. For other dogs, surgery to stabilize the knee may be the recommended long-term treatment.


In a cruciate ligament injury, the ligament that serves to help stabilize the knee joint tears or ruptures. This can be caused by a sudden movement or via slow degeneration over time.

With a sudden (acute) injury, the dog was likely completely normal before the occurrence that led him to three-leg it home from the park. In the more common (chronic), slow-burn kind of ligament degeneration, signs may appear overnight or after a rough day out, but it’s most likely been coming on for some time. In fact, most dogs with a cruciate ligament injury will display some evidence of knee problems in the veterinary exam room before the average owner ever notices anything. Sometimes, both knees are affected — usually one more than the other.

Middle-aged to older pets are more likely affected, although cruciate ligament injuries can (rarely) occur in dogs younger than 1 year of age. Any dog can injure a cruciate ligament, but some dog breeds seem genetically predisposed to this problem (see examples below).

Signs and Identification

The first sign of the disease is typically hind leg lameness. Acute cruciate ligament injury can be suddenly painful. Chronic cruciate ligament injury, on the other hand, can be more slowly painful. Some dogs may be only slightly lame while others are unable to place any weight on the affected limb. Other signs include:

  • Stiffness
  • A dog that sits abnormally because it no longer can or wants to flex its stifle joint
  • Difficulty rising
  • Joint swelling and/or muscle atrophy (wasting) in the knee area
  • Decreased activity level
Dogs (and sometimes cats) with underlying knee problems or arthritis can be at increased risk for future cruciate ligament problems. Same goes for dogs of certain breeds.

Affected Breeds

Any dog of any breed can suffer a cruciate ligament injury. The condition is rare in cats. Some large breed dogs, such as the Rottweiler, Labrador Retriever, Newfoundland, and Saint Bernard seem to have an increased risk of disease. But smaller dogs, like the Dachshund, Shih Tzu, Lhasa Apso, and Chihuahua, can also be affected.


Treatment recommendations for cruciate ligament injury are based on several factors, including the severity of the injury, the condition of other structures in the knee, and the size and overall health of the patient.

Medical management typically consists of rest, appropriate pain medication (such as pet-specific anti-inflammatory medications), and joint supplements. Once the acute phase has passed, it is very important to keep the dog’s weight under control and follow a veterinarian-approved exercise plan. In many cases, small dogs (less than 30 pounds) can do well with medical management. Medical treatment may also be recommended if the dog is not a good candidate for surgery.

Surgical treatment involves stabilizing the knee joint to create more normal movement. There are several surgical procedures that can accomplish this successfully. Some veterinarians perform the surgery themselves; others may refer this procedure to a veterinary orthopedic specialist. Some veterinarians can perform cruciate ligament surgery using arthroscopic surgical equipment.

After surgery, it is important to follow veterinary recommendations, such as limiting activity until the surgical site heals. Pain medications and physical therapy may be prescribed as needed.


Helping your pet maintain a healthy weight and good muscle tone can help ward off joint injuries. If your dog’s breed is predisposed to this issue or if your dog has already shown joint problems, be sure to discuss your pet’s activity and exercise schedule with your veterinarian.

This article has been reviewed by a Veterinarian.