Cruciate Ligament Injury

The most common cause of hind leg lameness in dogs is a cruciate ligament injury or degeneration. A dog’s cruciate ligaments are two ligaments in the their hind leg that cross over the knee. They connect the tibia to the femur (the bottom leg bone to the top leg bone) and are responsible for stabilising the knee joint, controlling movement and allowing the knee to bend and flex. The two cruciate ligaments are the cranial (anterior) ligament which is the one that runs at the front of the knee and the caudal (posterior) ligament at the back. The cranial cruciate ligament (CCL) is the one that typically causes problems with deterioration, possible tears or full ruptures.

Degeneration of the ligament is known as cranial cruciate ligament (CCL) disease. It is a progressive disease in which the ligament weakens or deteriorates over time due to a number of factors. It will often cause osteoarthritis of the knee joint and intermittent periods of lameness.This continual degeneration will often contribute to a small tear or full rupture of the ligament during normal daily activities. Less commonly a cruciate ligament tear or rupture can occur simply due to a sudden injury usually such as jumping, changing direction quickly or sharply or running.

Some factors that can contribute to the development of CCL disease and in turn ligament tear or rupture include;
* Abnormal or poor conformation (often genetically passed down)
* Genetically predisposed (ie. breed)
* Obesity / overweight great risk increase
* Age/older dog’s can degenerate or become weaker
* Osteoarthritis in the knee joint

Depending on the extent of the injury or degeneration of the CCL the symptoms may vary from slight lameness to unable to weight bear at all. Signs to look out for include;
* Pain or stiffness
* Swelling around the knee
* Lameness (sometimes intermittent, may rectify with rest)
* Trouble jumping into car or onto bed
* Stiffness or slow to rise from lying down
* Decreased activity level
* Muscle atrophy (muscle wastage)
* Dog’s that have torn or ruptured the ligament typically hold the injured leg with just the top of the toes touching the ground (called toeing)

If your dog is showing any of the above signs you should take them to see a veterinarian for a correct diagnosis and treatment options. There are surgical and nonsurgical management options available for the treatment of CLL disease or injury. The extent of the injury or progression of the disease and the level of knee instability will determine the correct form of treatment. Other factors that will be considered are the dog’s age, overall health, activity levels, body type and size. The outcome of any treatment option is to improve mobility and movement while reducing pain and inflammation. If the dog is overweight it is absolutely essential that their weight is reduced and managed for the best outcome.

With the correct treatment and management a dog can fully recover from a cruciate tear or rupture and cranial cruciate ligament disease can be controlled. Unfortunately though they will often end up injuring the other leg within a few years as there is usually an underlying factor (genetics, conformation or osteoarthritis) that contributes to the issue causing it to happen again. A dog with cruciate ligament disease or that has suffered a tear should be monitored and be on arthritis treatments and supplements.

If you ever have any concerns about your dog’s heath please contact your veterinarian for advice.

Originally published in My Pet Magazine Issue 15, Autumn/Winter 2018.
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